SEO BANDWAGON

SEO Bandwagon · Reference

SEO Glossary

640 SEO terms, defined in plain English. For 233 of them, the glossary also shows whether anyone still uses the term: each was measured across 23 years of Wikipedia revisions, and 23 of them are effectively obsolete.

0-9

100 Continue

An HTTP informational status code indicating that the server has received the start of a request and has not yet rejected it. RFC 9110 says the response tells a client that sent an Expect: 100-continue header to keep sending the request’s content; a client that made no such request can simply ignore the interim reply and wait for the final response.

Technical SEO

101 Switching Protocols

An HTTP informational status code indicating that the server will comply with a client’s request, sent in an Upgrade header, to change the connection’s protocol. RFC 9110 requires the server’s response to name the new protocol in its own Upgrade header field, and says a server should only agree to switch when doing so benefits the connection, such as moving to a newer version of HTTP.

Technical SEO

200 OK

An HTTP success status code indicating that a request has succeeded. RFC 9110 says a 200 response to a GET request carries a representation of the requested resource. Google may index the content of a 2xx response but doesn’t guarantee it, and Search Console reports a soft 404 when the page looks empty or like an error.

Technical SEO

201 Created

An HTTP success status code indicating a request has resulted in a new resource being created, typically after a POST. RFC 9110 says the response identifies the new resource with a Location header field or, failing that, the request’s own target URI. Google handles 201 like 200: it may index the content of a 2xx response but doesn’t guarantee it.

Technical SEO

202 Accepted

An HTTP success status code indicating a request was accepted for processing that has not finished, with no guarantee the action will complete. RFC 9110 gives HTTP no way to send a status code later, once such work finishes. Google says its crawlers wait a limited, user-agent-dependent time for the content, then pass on whatever arrived to the next processing step, such as indexing.

Technical SEO

203 Non-Authoritative Information

An HTTP success status code indicating a request succeeded but a proxy modified the origin server’s response before passing it on. RFC 9110 says a transforming proxy sends this instead of 200 to flag that headers or content were altered in transit, a fact that can matter for later cache validation along the same path.

Technical SEO

206 Partial Content

An HTTP success status code indicating a server is fulfilling a range request by returning only part of the requested resource. RFC 9110 requires the response to carry a Content-Range header naming the bytes it contains; the specification’s own examples show the mechanism serving a partial image and a multi-part PDF transfer.

Technical SEO

207 Multi-Status

An HTTP success status code indicating that one WebDAV response carries the separate outcomes of several independent operations. RFC 4918 says the response body is an XML document whose multistatus element lists a status code per resource, so a WebDAV operation such as COPY or MOVE across many resources can partly succeed and partly fail at once; MDN Web Docs notes browsers never encounter the code outside a WebDAV client.

Technical SEO

300 Multiple Choices

An HTTP redirection status code indicating that a resource has more than one representation and the client can pick one. RFC 9110 lets the server name a preferred choice in a Location header for automatic redirection, but MDN Web Docs notes most clients have no built-in way to choose automatically, so the code sees little real use next to server-driven negotiation.

Technical SEO

301 redirect

An HTTP redirection status code indicating that a resource has permanently moved to a new URL, given in the response’s Location header. RFC 9110 says the code suggests that clients able to edit links replace references to the old URL. Google treats a 301 as a strong signal that the target should become canonical and shows the new URL in search results, and says a permanent redirect loses no PageRank.

Technical SEO

302 redirect

An HTTP redirection status code indicating that a resource has moved temporarily to a different URL, given in the response’s Location header. RFC 9110 tells clients to keep using the original URL for future requests. Google follows a 302 by default but treats it as only a weak signal, keeping the original URL in search results, though the target can still be indexed if other canonicalization signals point to it.

Technical SEO Technical SEO audit →

303 See Other

An HTTP redirection status code indicating that the server is redirecting the client to a different resource, fetched with GET or HEAD, as an indirect answer. RFC 9110 says the code mainly lets a POST’s result be shown at its own bookmarkable, cacheable URL. Google treats 303 like 302, as only a weak signal, keeping the original URL in search results.

Technical SEO

304 Not Modified

An HTTP redirection status code indicating that a client’s cached copy of a resource is still valid, so the server doesn’t send the content again. RFC 9110 says the server sends it when a conditional GET or HEAD request’s If-None-Match or If-Modified-Since condition shows the cache is current. Google says a 304 may lead its indexing pipeline to recalculate signals for the URL, with no other effect on indexing.

Technical SEO

307 Temporary Redirect

An HTTP redirection status code indicating that a resource has moved temporarily to a different URL, where the client must repeat the request with its original method. RFC 9110 says 307 was added so a redirected POST keeps its method and content, unlike a 302, where a client may switch to GET. Google treats 307 like 302, as only a weak signal, keeping the original URL in search results.

Technical SEO

308 Permanent Redirect

An HTTP redirection status code indicating that a resource has moved permanently to a new URL, where the client must repeat the request with its original method. RFC 9110 says 308 was added so a redirected POST keeps its method and content, unlike a 301, where a client may switch to GET, and notes it may not be recognized everywhere. Google treats 308 like 301, as a strong signal that the target should become canonical.

Technical SEO

401 Unauthorized

An HTTP client error status code indicating a request lacks valid credentials for the resource, sent with a WWW-Authenticate header naming how to authenticate. RFC 9110 lets a client retry with new credentials. Google treats the 4xx codes it documents, except 429, alike: a URL returning one is kept out of Google Search’s index, and Google crawls it less and less often. Google says a 401 or 403 doesn’t lower its crawl rate.

Technical SEO

402 Payment Required

An HTTP client error status code that the HTTP specification reserves for future use and otherwise leaves undefined. RFC 9110 assigns the number but specifies no required behavior; MDN Web Docs says the code was created with digital payment systems in mind, but no standard convention for its use has emerged, so systems that send it define their own meaning.

Technical SEO

403 Forbidden

An HTTP client error status code indicating that a server understood a request but refuses to carry it out, treating any credentials sent as insufficient. RFC 9110 lets a server hide a resource’s existence by sending 404 instead. Google treats the 4xx codes it documents, except 429, alike: a URL returning one is kept out of Google Search’s index, and Google crawls it less and less often. Google says a 401 or 403 doesn’t lower its crawl rate.

Technical SEO

404 Not Found

An HTTP client error status code indicating the server found no current resource at the requested URL, without saying whether that’s temporary or permanent. RFC 9110 prefers 410 when the server knows the condition is likely permanent. Google treats the 4xx codes it documents, except 429, alike: a URL returning one is kept out of Google Search’s index, and Google crawls it less and less often.

Technical SEO

405 Method Not Allowed

An HTTP client error status code indicating the server recognizes the request’s method but the target resource doesn’t support it. RFC 9110 requires the server to list the methods the resource does support in an Allow header field, and makes a 405 response heuristically cacheable unless the method definition or explicit cache controls say otherwise.

Technical SEO

406 Not Acceptable

An HTTP client error status code indicating no representation of a resource matches what the client’s Accept headers said it would take. RFC 9110 says the server should list the representations it can offer instead of guessing with a default one; MDN Web Docs notes a server may prefer to send a 200 with its best-available representation rather than reject the request outright.

Technical SEO

407 Proxy Authentication Required

An HTTP client error status code indicating a client must authenticate with a proxy before that proxy will forward its request. RFC 9110 models 407 directly on 401 but scopes it to the proxy between client and origin server, whose Proxy-Authenticate header must name an acceptable challenge before the client can retry with credentials.

Technical SEO

408 Request Timeout

An HTTP client error status code indicating a server gave up waiting for a request that never fully arrived, and closed the connection. RFC 9110 lets the client simply retry the request on a new connection; MDN Web Docs notes some servers send this on an idle connection with no prior request at all, while others simply close the connection without sending it.

Technical SEO

409 Conflict

An HTTP client error status code indicating a request clashes with the resource’s current state and cannot be applied as sent. RFC 9110 points to a versioned PUT as the typical case, where an edit collides with an earlier change to the same resource; the server should return enough detail in its response for a user to resolve the conflict and resubmit.

Technical SEO

410 Gone

An HTTP client error status code indicating a resource’s removal from the origin server was deliberate and is expected to stay that way. RFC 9110 says the code mainly tells recipients that the removal is intentional so they can remove links to it, unlike a 404, which is silent on permanence. Google treats the 4xx codes it documents, except 429, alike: a URL returning one is kept out of Google Search’s index, and Google crawls it less and less often.

Technical SEO

412 Precondition Failed

An HTTP client error status code indicating a condition set by the request’s If-Match or If-Unmodified-Since header was not met. RFC 9110 lets a client attach such a precondition to a PUT or similar method so the server rejects the request if the resource changed since the client last read it, guarding against one editor silently overwriting another’s update.

Technical SEO

413 Content Too Large

An HTTP client error status code indicating that the server refuses a request because its content is larger than the server will process. RFC 9110 lets the server end the request or close the connection, and says it should send a Retry-After header field when the condition is temporary.

Technical SEO

415 Unsupported Media Type

An HTTP client error status code indicating that the server refuses a request because its content is in a format the target resource’s method doesn’t support. RFC 9110 says the mismatch can come from the request’s Content-Type or Content-Encoding header, or from inspecting the data itself, and points servers to name accepted types in an Accept response header field.

Technical SEO

417 Expectation Failed

An HTTP client error status code indicating that at least one server on the request’s path could not meet the expectation set in its Expect header field. RFC 9110 defines only one expectation, “100-continue,” and says a server may return 417 when the field names any other expectation it cannot meet.

Technical SEO

418 I’m a teapot

An HTTP client error status code that RFC 9110 reserves as unused, after an April Fools’ RFC assigned it to a joke protocol for controlling coffee pots. RFC 2324’s Hyper Text Coffee Pot Control Protocol defined it on April 1, 1998, for a teapot that cannot brew coffee; RFC 9110 keeps the number reserved rather than reassigning it, citing repeated real-world use of the joke.

Technical SEO

421 Misdirected Request

An HTTP client error status code indicating that the request reached a server unable or unwilling to give an authoritative response for its target URI. RFC 9113 says HTTP/2 can reuse one connection for several hostnames sharing a certificate; if that misdirects a request, RFC 9110 lets the server reply 421 so the client retries the same request over a fresh connection instead.

Technical SEO

422 Unprocessable Content

An HTTP client error status code indicating that a server understood a request’s content type and syntax but could not act on the instructions it contained. RFC 9110 gives the example of well-formed XML instructions that are semantically wrong, and separates this code from 415, which covers a content type the server cannot handle at all.

Technical SEO

423 Locked

An HTTP client error status code, defined for WebDAV, indicating that a lock on a method’s source or destination resource blocks the request. RFC 4918 says the response should name a precondition or postcondition code, such as lock-token-submitted; IANA’s status code registry credits 423 to RFC 4918 alone, not to core HTTP’s RFC 9110.

Technical SEO

424 Failed Dependency

An HTTP client error status code, defined for WebDAV, indicating that a method could not run because an action it depended on had failed. RFC 4918 gives the example of a PROPPATCH request with several property updates: once one update fails, the rest fail too and each can return this code; IANA’s status code registry credits 424 to RFC 4918 alone, not to core HTTP’s RFC 9110.

Technical SEO

426 Upgrade Required

An HTTP client error status code indicating that a server refuses a request on the current protocol but might accept it after the client upgrades to another. RFC 9110 requires the server to name the acceptable protocols in an Upgrade header field, the same field a client can use on the same connection to request a switch to a protocol such as WebSocket.

Technical SEO

431 Request Header Fields Too Large

An HTTP client error status code indicating that a server won’t process a request because one or more of its header fields are too large. RFC 6585 says a response using this code must not be cached, and recommends naming the specific oversized field when only one header field is at fault.

Technical SEO

444 No Response

A non-standard HTTP status code that nginx uses internally to close a connection to a client without sending any response headers or body. nginx’s source code comments identify this as one of nginx’s own HTTP codes: it closes the connection without sending a response header, and the reset_timedout_connection directive can send a TCP reset for connections closed this way.

Technical SEO

451 Unavailable For Legal Reasons

An HTTP client error status code indicating that a server denies access to a resource because of a legal demand. RFC 7725 says this kind of demand typically affects internet service providers and search engines most directly, and recommends the response body name the party demanding removal and the law involved.

Technical SEO

499 Client Closed Request

A non-standard HTTP status code that nginx logs when a client closes the connection before nginx can send the HTTP response header. nginx’s source code says HTTP defines no code for this case, so the project introduced its own to log the event; because no header was sent, the code never reaches the client as a real response.

Technical SEO

500 Internal Server Error

An HTTP server error status code indicating that a server met an unexpected condition that stopped it from fulfilling a request. RFC 9110 says 5xx codes apply to any request method and that a server should explain the error in the response body, except in reply to a HEAD request. Google’s crawlers slow down temporarily when a site returns 5xx errors, and Google Search eventually drops indexed URLs that keep returning one.

Technical SEO

501 Not Implemented

An HTTP server error status code indicating that a server doesn’t support the functionality a request requires. RFC 9110 gives an unrecognized method, one the server can’t support for any resource, as the typical cause, and makes a 501 response heuristically cacheable unless the method definition or explicit cache controls say otherwise.

Technical SEO

502 Bad Gateway

An HTTP server error status code indicating that a server acting as a gateway or proxy got an invalid response from the inbound server it contacted. RFC 9110 ties both 502 and 504 to a gateway or proxy relaying to an upstream server, unlike 503, which any server can return on its own. Google’s crawlers slow down temporarily when a site returns 5xx errors, and Google Search eventually drops indexed URLs that keep returning one.

Technical SEO

503 Service Unavailable

An HTTP server error status code indicating that a server can’t handle a request right now because of temporary overload or scheduled maintenance. RFC 9110 lets the server add a Retry-After header field suggesting a wait time, and notes the code’s existence doesn’t require its use — an overloaded server may just refuse the connection instead. Google’s crawlers slow down temporarily when a site returns 5xx errors, and Google Search eventually drops indexed URLs that keep returning one.

Technical SEO

504 Gateway Timeout

An HTTP server error status code indicating that a server acting as a gateway or proxy got no response in time from an upstream server it relied on. RFC 9110 separates it from 502 by cause: the upstream server didn’t answer in time, rather than answering with something invalid.

Technical SEO

A

Above the fold

The part of a webpage a visitor sees on screen before scrolling down. Google said sites with little content above the fold, or with ads filling much of that first screen, might not rank as highly after its page layout algorithm launched on January 19, 2012; Largest Contentful Paint also measures only elements visible in the viewport.

On-page and content

Absolute URL

A URL that includes every part needed to locate a resource on its own, such as the scheme and host, without depending on the page it appears in. The WHATWG URL Standard formally calls this an absolute-URL string, distinct from a relative URL such as /path or //host/path, which borrows its missing parts from the document that contains it. Google recommends absolute URLs, not relative paths, in rel="canonical" link elements.

Technical SEO

A/B testing In use · 69%

A method of testing two or more versions of a page or element against each other to see which performs better with real visitors. Google Search Central tells site owners not to cloak test pages, to add rel=“canonical” links on variant URLs pointing to the original, and to use 302 rather than 301 redirects so the redirect is understood as temporary while the test runs.

First seen 2013 · Peaked 2017 · Retains 69% of peak Analytics and rank tracking

Active users Current · 100%

In Google Analytics 4, the number of distinct users who triggered at least one engagement-related event on a site or app during a chosen date range. GA4 counts a user as active after an engaged session, or after Analytics collects a first_visit or first_open event, or an engagement_time_msec parameter; reports show only active users, though exports to Google Ads include inactive ones too.

First seen 2006 · Peaked 2023 · Retains 100% of peak Analytics and rank tracking

Adaptive design

A web design approach that practitioners describe as switching between several fixed-width layouts at set breakpoints, screen widths where a page’s layout changes. Unlike responsive web design, which Google says serves identical HTML on one URL while the display adapts to screen size, adaptive design is not among the three mobile configurations Google names; Google recommends responsive design as the easiest to implement and maintain.

Technical SEO

AEO tool sprawl

The proliferation of separate, often overlapping software tools that practitioners use to track a brand’s visibility across AI answer engines, each measuring citations, prompts or rankings in its own way. Google says it “doesn’t evaluate or endorse third-party SEO tools,” which have no access to its internal ranking data, and tells site owners to check whether advice from “AEO” or “GEO” services matches its official guidance.

AI search and GEO

Agent economy

An economy in which autonomous AI agents negotiate, transact and complete purchases on behalf of the people or businesses they represent, interacting with other agents or services programmatically. A May 2025 research paper titled “The Agentic Economy” modeled how assistant and service agents could transact directly; Google’s Agent Payments Protocol, announced September 16, 2025, describes itself as “an open protocol for the emerging Agent Economy.”

AI search and GEO

Agentic AEO

Answer engine optimization aimed at AI agents that act on a user’s behalf, such as shopping or research agents, rather than at the person typing a prompt directly. Google’s guide discusses these agents under “agentic experiences,” noting that browser agents may analyze a page’s screenshots, DOM structure and accessibility tree to complete a task, instead of a person reading the page.

AI search and GEO

Agentic browser

A web browser with a built-in AI agent that navigates sites, fills forms and completes multi-step tasks for the user, instead of only rendering pages for a human to operate. web.dev’s guidance for site owners says such agents read a page as a screenshot, raw HTML or an accessibility tree rather than as a human sees it, so stable layout and semantic HTML change whether the agent can act.

AI search and GEO

Agentic experiences

Interactions in which an AI agent, rather than a person, browses a website or app to complete a task, such as comparing products or making a booking. Google’s guide to generative AI search tells site owners to review agent-friendly website best practices, since a browser agent may analyze a page’s screenshots, DOM structure and accessibility tree instead of viewing it as a person does.

AI search and GEO

Agentic search

A search experience in which an AI agent plans and carries out multiple steps toward a goal, instead of returning a single list of links. Google positions AI Mode for “queries where further exploration, reasoning, or complex comparisons are needed” and documents a query fan-out technique that issues several related searches before composing a response.

AI search and GEO

AI agent

A software system, built on an AI model, that decides its own steps and calls tools to complete a multi-step task with limited moment-to-moment human direction. Anthropic’s Agent SDK docs define an agent as an application that decides its own steps and invokes tools, such as editing code or running shell commands, to finish a task; OpenAI’s Agents documentation and Google’s Search Central guidance describe the same combination of autonomy and tool use.

AI search and GEO

AI-assisted editing

The use of generative AI tools to help research, structure or revise content that a person still directs and takes responsibility for, rather than to generate finished pages unsupervised. Google says generative AI can be useful “when researching a topic, and to add structure to original content,” and recommends telling readers how automation was used; using it to publish many pages with no added value violates Google’s spam policies.

AI search and GEO

AI citation

A link or source reference that an AI system shows alongside a generated answer to credit the page it drew on, such as a link under a Google AI Overview. Google says AI Overviews and AI Mode identify supporting web pages and display links to them alongside the response; a page must already be indexed and eligible for a snippet to be shown this way, and needs no special markup or file.

AI search and GEO

AI connector

A feature that lets an AI assistant read data from, or take actions in, a separate application or service, such as a calendar or a code repository, during a conversation. Anthropic introduced the Model Context Protocol in November 2024 as “an open standard” for connecting AI assistants to the systems that hold a user’s data, and donated it to the Linux Foundation’s Agentic AI Foundation on December 9, 2025; Anthropic’s Usage Policy requires MCP servers in its Connector Directory to meet a directory policy.

AI search and GEO

AI content guardrails

Rules and technical checks that constrain what a generative AI system will produce or act on, meant to stop harmful, deceptive or policy-violating output before it reaches a user. Anthropic’s engineering guidance describes a guardrails pattern in which one model instance handles a user’s request while a separate instance screens it for policy violations; Anthropic’s Usage Policy and Google’s spam policies each set their own platform-specific rules for generated output.

AI search and GEO

AI content score

A third-party tool’s proprietary rating of how likely a page is to be used or cited by an AI system, with no standard method shared across tools. Google’s own guidance warns site owners to be wary of third-party tools that claim “acceptable” or “approved” status, since Google says it “doesn’t evaluate or endorse third-party SEO tools” and that “these tools don’t have access to Google’s internal ranking data.”

AI search and GEO

AI crawlability

A measure of how easily an AI company’s crawler can fetch and read a site’s content, governed by the same robots.txt rules and server responses that control search-engine crawling. RFC 9309 standardizes how a robots.txt file grants or denies a named crawler access; OpenAI and Perplexity say each of their robots.txt settings works independently, though their user-triggered fetchers may not follow these rules.

AI search and GEO

AI crawler

An automated bot that an AI company operates to fetch web pages for training a model, answering a live query, or both, identified by its own user-agent string. OpenAI runs separate crawlers for training (GPTBot) and search (OAI-SearchBot) so a site can allow one and disallow the other; Perplexity says PerplexityBot “is not used to crawl content for AI foundation models” at all, only to surface pages in search.

AI search and GEO

AI crawler analytics

The practice of measuring which AI companies’ bots visit a site and how often, usually read from server logs rather than from a standard analytics tag. Each crawler identifies itself with a distinct user-agent string, such as GPTBot, OAI-SearchBot or PerplexityBot, and OpenAI and Perplexity each publish the IP ranges their bots fetch from, which log analysis can match against recorded requests.

AI search and GEO

AI features (Google Search)

Google’s collective name for the generative AI experiences in Google Search, currently AI Overviews and AI Mode, which share one set of eligibility rules, content controls and Search Console reports. Google says a page needs only to be indexed and eligible for a snippet to appear in them; the nosnippet, data-nosnippet, max-snippet and noindex controls limit what they show, and their appearances count in Search Console’s “Web” performance data and in its Generative AI performance report.

AI search and GEO

AI-generated content Current · 100%

Web content, such as text, images or product listings, produced fully or partly by a generative AI system rather than written or created by a person from scratch. Google’s spam policies list using generative AI tools “to generate many pages without adding value for users” as an example of scaled content abuse, regardless of how the content was made; for AI-generated images and product data in Merchant Center, Google requires separate labeling and IPTC source metadata.

First seen 2023 · Peaked 2026 · Retains 100% of peak AI search and GEO

AI knowledge cutoff

The date after which an AI model’s training data stops, so the model has no built-in knowledge of events or facts from after that point. OpenAI publishes a “Knowledge cutoff” date for each model on its model comparison page; Anthropic’s models page instead lists a “Reliable knowledge cutoff” for each model and points to its Transparency Hub for the separate training-data cutoff.

AI search and GEO

AI Mode

A Google Search mode that answers complex, multi-part questions with an AI-generated response and links to supporting pages, built for queries needing exploration, reasoning or comparison. Google says AI Mode and AI Overviews can rely on different models and techniques, so their responses and links differ. Google’s documentation changelog for March 5, 2025, says AI Mode is “now available in Search Labs,” and its entry for June 16, 2025, says AI Mode data now counts toward Search Console’s Performance report totals.

AI search and GEO

AI optimization

The broadest practitioner label for adapting a website to AI systems, covering content, crawler access and agent readiness, and taking in narrower labels such as AEO, GEO and LLMO. Google’s documentation changelog calls its guidance on generative AI features in Search the “AI optimization guide”; that guide covers content, technical structure, crawling, local and product data and AI agents, and says the features rest on Google’s core Search ranking and quality systems.

AI search and GEO AI search optimization →

AI Overview citation rate

A practitioner metric for how often a domain or page appears as a supporting link within Google’s AI Overviews, usually estimated by a third-party tool rather than reported by Google. Search Console’s Generative AI performance report counts impressions of a site’s links in AI Overviews and AI Mode together, grouped by page, country, date or device, so a rate for AI Overviews alone is not a figure Google publishes.

AI search and GEO

AI Overviews

A Google Search feature that shows an AI-generated summary of a topic with links to supporting web pages, appearing only when Google’s systems judge it adds to classic results. Google says a page needs no special files or markup to appear as a supporting link, only to be indexed and eligible for a snippet; a Search Console control rolled out to all sites on August 31, 2026, lets owners exclude their site.

AI search and GEO AI search optimization →

AI prompt tracking

The practice of running a fixed set of prompts against AI chat and search systems on a schedule, to monitor whether a brand or page appears in the answers. Google warns site owners that no third-party tool has access to its internal ranking or AI systems, so a prompt-tracking tool observes only the answer it receives for each run rather than Google’s underlying retrieval or ranking process.

AI search and GEO

AI prompt volume

A practitioner estimate of how often a given prompt or topic is asked across AI chat and search systems, used as an AI-search stand-in for keyword search volume. No AI platform publishes this figure, so third-party tools estimate it by their own methods; Google says it “doesn’t evaluate or endorse third-party SEO tools,” which have no access to its internal ranking data, and warns against any that claim Google’s approval.

AI search and GEO

AI-ready content

Content structured and written clearly enough for an AI system to parse and reuse accurately, a goal practitioners pursue even though Google says no special format is required. Google’s generative AI guide says there is no ideal page length and no need to “chunk” content into small pieces, since its systems parse multiple topics on a page and surface the relevant part; Google separately recommends organizing pages by paragraphs and sections, with headings that give readers a clear structure.

AI search and GEO

AI SEO

A practitioner label for optimizing for AI-powered search that treats the work as part of search engine optimization rather than a new discipline, the view Google also takes. Google’s guide to generative AI search says that, from its perspective, optimizing for generative AI search “is optimizing for the search experience, and thus still SEO,” and that the same foundational best practices apply to both.

AI search and GEO AI search optimization →

AI slop

Digital content made with generative AI that is perceived as high-volume and low-effort, adding little value for the person who encounters it. Google’s spam policies ban using generative AI tools “to generate many pages without adding value for users” under its scaled content abuse policy; the term itself is informal, with no technical or platform-owned definition.

AI search and GEO

AI traffic

Website visits referred by AI chat assistants and AI-powered search features, as distinct from clicks on classic search results. Google Analytics defines a default “AI Assistant” channel for visits from sources such as ChatGPT, Gemini, DeepSeek, Copilot or Grok, but excludes Google’s own AI Overviews and AI Mode, which it still counts under “Organic Search.”

AI search and GEO

AI visibility

A measure of how often, and how prominently, a brand or its pages appear in the answers, summaries or citations that AI-powered search and chat systems produce. Search Console’s Generative AI performance report counts impressions of a site’s links in Google’s own AI Overviews and AI Mode, but Google says no third-party tool has access to its internal ranking or AI systems, so a cross-platform visibility score is always an outside estimate, not a published metric.

AI search and GEO

AI while browsing

A retired Google Search feature that showed AI-generated key points for a webpage while a person browsed it, separate from Google’s AI Overviews. Google’s paywalled-content documentation said the feature would not show key points for articles marked as paywalled with isAccessibleForFree: false structured data.

AI search and GEO

AJAX Asynchronous JavaScript and XML Fading · 52%

A term, coined in 2005, for a web-development technique that updates parts of a page by exchanging data with a server in the background, without reloading the whole page. Jesse James Garrett of Adaptive Path published the term on February 18, 2005, as shorthand for “Asynchronous JavaScript + XML,” citing Google Suggest and Google Maps as early examples; the essay describes Ajax not as one technology but several — including XHTML, CSS, the DOM and XMLHttpRequest — working together.

First seen 2005 · Peaked 2012 · Retains 52% of peak Web fundamentals

Algorithm update In use · 77%

A change Google makes to its search algorithms or ranking systems, ranging from routine adjustments to major, publicly documented releases. Google logs these on its Search Status Dashboard with a category, start date and duration; a core update is one specific, broad type that happens several times a year.

First seen 2006 · Peaked 2015 · Retains 77% of peak Algorithms and updates

Alt text Obsolete · 0%

The text alternative for an image, given in the alt attribute the HTML Standard defines, which screen readers read aloud and browsers show if the image fails to load. The HTML Standard says that, except where it specifies otherwise, the alt attribute must be present, non-empty and an appropriate replacement for the image. Google calls alt text the most important attribute for providing metadata about an image, uses it with computer vision and page content to understand what an image shows, and warns against stuffing it with keywords.

First seen 2021 · Peaked 2021 · Retains 0% of peak On-page and content Free SEO Chrome extension →

AMP Accelerated Mobile Pages

A web components framework for building fast-loading pages, which Google announced in October 2015 and the OpenJS Foundation now governs. Google Search indexes AMP pages like other web pages and holds them to the same standards, and it now takes searchers directly to the publisher’s own AMP pages rather than a cached copy.

Technical SEO

Anchor text Fading · 50%

The visible, clickable words of a link, which Google’s own documentation also calls “link text.” Google says this text “tells people and Google something about the page you’re linking to,” asks for it to be descriptive rather than generic phrases like “click here,” and warns that cramming keywords into it can violate its spam policies.

First seen 2004 · Peaked 2005 · Retains 50% of peak Links and authority

Answerability

A measure of how directly and completely a page answers a specific question, which practitioners expect to raise its chances of appearing in a featured snippet or an AI Overview. Google says a page must be indexed and eligible for a snippet before AI Overviews or AI Mode will link to it as a source, so a page that can’t show a snippet can’t appear in either feature, however directly it answers the query.

AI search and GEO

Answer engine Current · 100%

An AI-powered search system built to give a direct, synthesized answer to a question, rather than only a ranked list of links to other pages. Perplexity’s own homepage describes it as “a free AI-powered answer engine that provides accurate, trusted, and real-time answers to any question”; Google’s guide to generative AI search lists “AEO,” for answer engine optimization, among terms for work aimed at visibility in AI search experiences.

First seen 2010 · Peaked 2026 · Retains 100% of peak AI search and GEO

Answer engine optimization

The practice of optimizing a page to supply the direct answer that an answer engine, such as Perplexity, gives to a specific question. Google’s guide defines the abbreviation (“‘AEO’ stands for ‘answer engine optimization’”) and groups it with GEO as terms for work on visibility in AI search experiences, which Google says is “still SEO.”

AI search and GEO AI search optimization →

Applebot

The web crawler Apple uses to gather pages for search features across its ecosystem, including Spotlight, Siri and Safari; its data may also help train Apple’s foundation models. Apple says allowing Applebot in robots.txt lets a site’s content appear in search results in those products; Applebot renders pages like a browser, obeys robots meta tags and follows a site’s Googlebot rules when none name it. Keeping content out of model training takes a separate Applebot-Extended rule.

AI search and GEO

Applebot-Extended

A secondary Apple user agent that lets a site opt its content out of training Apple’s generative AI models without blocking Applebot itself. Apple says disallowing Applebot-Extended in robots.txt keeps content Applebot crawls out of training for Apple’s foundation models while pages stay eligible for search results in Spotlight, Siri and Safari; Applebot-Extended crawls nothing itself and only governs how Applebot’s data is used.

AI search and GEO

Apple Business

A free Apple platform that combines built-in device management, business email and calendar, and tools to manage how a business appears across Apple Maps and Apple’s other apps. A business claims its location on Apple Maps, then edits a place card — photos, hours and other details — that displays across Maps, Safari and Spotlight. Apple Business also reports location insights on how customers find and interact with the business on Maps, including searches, views and taps on actions.

Local SEO

Apple Business Connect

A free Apple tool that let a business owner create and edit a Maps place card controlling how the business appeared across Apple Maps and other Apple apps. Business Connect place cards carried photos, location details and hours; Apple said existing Business Connect data, including claimed locations, would migrate to Apple Business automatically.

Local SEO

Apple Maps Current · 100%

Apple’s mapping and navigation app that provides turn-by-turn driving, walking, cycling and transit directions along with business listings. Apple says businesses manage their Maps place cards, including photos, location details and hours, through Apple Business.

First seen 2012 · Peaked 2026 · Retains 100% of peak Local SEO

Artificial intelligence Current · 94%

An umbrella term for computer systems, including machine learning and large language models, built to perform tasks that have traditionally required human intelligence, such as making predictions or decisions. NIST defines an “AI system” as “an engineered or machine-based system that can, for a given set of objectives, generate outputs such as predictions, recommendations, or decisions influencing real or virtual environments,” operating with varying autonomy; this glossary uses “AI” for the systems behind AI search features, AI agents and AI content tools.

First seen 2006 · Peaked 2025 · Retains 94% of peak AI search and GEO

Astroturfing In use · 74%

Coordinated fake reviews, comments or social activity made to look like independent, grassroots opinion in order to promote or attack a business. The FTC’s rule on consumer reviews and testimonials, in effect since October 2024, bars businesses from writing or buying reviews that misrepresent the reviewer’s existence or experience, and Google’s Maps content policy separately defines “fake engagement” as “content that does not represent a genuine experience.”

First seen 2007 · Peaked 2020 · Retains 74% of peak Spam and black hat

Attribution model

A rule or algorithm that assigns credit for a conversion among the multiple touchpoints a user reached before completing it. Google says it made data-driven attribution “the default attribution model in Google Ads and Google Analytics 4,” alongside “Paid and organic last click” and “Google paid channels last click.” GA4 dropped what Google calls “the first click, linear, time decay, and position-based attribution models” in November 2023, after Google said in April 2023 that any conversion actions still assigned to them would move to data-driven attribution starting that September.

Analytics and rank tracking

Auto-generated content

Bing’s term for large amounts of content produced without editorial oversight or quality control, which Bing says often lacks usefulness, accuracy and originality. Bing groups this with cloaking, keyword stuffing and scraped content among the practices its guidelines say can reduce a site’s ranking eligibility or suppress its visibility in Bing and Copilot results.

Spam and black hat

B

B2B local SEO

The practice of applying local search optimization — a Google Business Profile, local content and citations — to a business that sells to other businesses rather than consumers. Google's Business Profile guidelines require a physical location customers can visit or a service area the business travels to.

Local SEO

B2B SEO

Search engine optimization aimed at the researchers and buyers at other businesses, rather than individual consumers, as the audience who chooses a company’s products or services. Google’s Merchant Center guidance for Shopping ads says the program “doesn’t include a dedicated business-to-business experience,” though it notes that companies selling to other businesses often advertise there successfully.

Search fundamentals

Backlinks Fading · 43%

Links from pages on other websites that point to a page on a given site. Search Console Help defines a backlink the same way; its Links report, which groups external links by root domain, shows “a sample” rather than every link. Google says PageRank, which uses links, remains part of its core ranking systems but is one signal among many.

First seen 2004 · Peaked 2005 · Retains 43% of peak Links and authority SEO services →

BackRub

The search engine Larry Page and Sergey Brin built as Stanford University graduate students, using the links between pages to judge each page’s importance. Google’s own history page says they called it Backrub, then soon renamed it Google, and that Google Inc. was incorporated in 1998 after early investment from Sun co-founder Andy Bechtolsheim; the original 1997 Stanford project page spelled it BackRub, the spelling used here.

Algorithms and updates

Bait and switch Fading · 35%

An advertising practice, defined by US federal rules as an insincere offer to sell one product mainly to switch the buyer to another, usually costlier one. The FTC’s Guides Against Bait Advertising define the practice as luring buyers in order “to switch consumers from buying the advertised merchandise.” In search, practitioners apply the phrase to Google’s separate misleading functionality policy, which bans sites that “trick users into thinking they would be able to access some content or services but in reality can’t.”

First seen 2004 · Peaked 2004 · Retains 35% of peak Spam and black hat

Bandwidth Fading · 41%

A network connection’s data-carrying capacity: how much information it can transfer in a given time, usually expressed in bits per second such as Mbps or Gbps. MDN Web Docs gives megabits-per-second (Mbps) and gigabits-per-second (Gbps) as typical units for this rate, and a connection with too little of it lengthens the Time to First Byte a visitor’s browser waits for a page’s first bytes to arrive.

First seen 2004 · Peaked 2008 · Retains 41% of peak Web fundamentals

BERT Bidirectional Encoder Representations from Transformers Current · 96%

An AI language model, applied to Search starting October 2019, that helps Google understand how combinations of words express meaning and intent in a query. Google said BERT would help Search better understand one in ten English-language searches in the US at launch, expanding over time; the underlying model, described in a 2018 Google research paper, weighs a word against its full surrounding context rather than reading left to right.

First seen 2020 · Peaked 2024 · Retains 96% of peak Algorithms and updates

Bingbot In use · 60%

The web crawler Bing uses to discover and fetch pages for its search index. Bing says Bingbot handles most of its crawling each day and, because user-agent strings are easy to spoof, offers a Verify Bingbot tool to confirm a request’s IP. Bing announced in April 2022 that Bingbot’s user agent would become evergreen, tracking the stable Microsoft Edge rendering engine, and that it would retire the old fixed string by fall 2022.

First seen 2010 · Peaked 2012 · Retains 60% of peak Technical SEO Technical SEO audit →

Bing Places for Business

Microsoft's free service for adding and managing a business listing that appears on Bing search results. Microsoft says owners claim an existing listing or add a new one, verify it with a PIN sent to the business address, phone or email, and can add multiple locations at once with a bulk upload tool.

Local SEO Local SEO →

Bing Webmaster Tools Current · 100%

A free tool from Microsoft that shows how a site performs in Bing search, letting site owners verify ownership, submit sitemaps and use reports to improve their search ranking. Bing’s own help center says the tool helps site owners understand and improve performance in Bing search, and Bing also publishes a web API so owners can pull the same data programmatically.

First seen 2009 · Peaked 2026 · Retains 100% of peak Analytics and rank tracking

Black hat SEO In use · 76%

Search engine optimization tactics that a site uses to manipulate rankings in violation of a search engine’s published guidelines. Google’s Search Essentials sort behavior into technical requirements, spam policies and best practices without a hat category, and its spam policies define spam as techniques that manipulate Search systems or deceive users.

First seen 2004 · Peaked 2017 · Retains 76% of peak Spam and black hat When SEO Was Spam →

Blog Fading · 56%

A website, or a regularly updated section of one, that publishes dated posts in reverse-chronological order. Schema.org’s Blog type treats each entry as a BlogPosting; Google’s Article structured data accepts BlogPosting alongside Article and NewsArticle, which can help it show a richer title, image and publish date for the post in Search.

First seen 2004 · Peaked 2007 · Retains 56% of peak On-page and content

Boolean search Fading · 57%

A search query built from the logical operators AND, OR and NOT to combine, broaden or exclude terms. Google Search Help lists a minus sign to exclude a word, which works like Boolean NOT, and quotation marks for an exact phrase, while Google’s search-operator documentation lists no AND or OR operator.

First seen 2004 · Peaked 2009 · Retains 57% of peak Search fundamentals

Bounce rate

In Google Analytics 4, the share of sessions that did not qualify as engaged, the inverse of engagement rate. A session counts as engaged if it lasts 10 seconds or more, includes a key event, or has 2 or more page or screen views; GA4 Help states directly that bounce rate “is the opposite of the engagement rate.”

Analytics and rank tracking

Brand authority

A practitioner term for how much a search or AI system favors a company or publication for its overall reputation, apart from any single page’s own authority. Google’s E-E-A-T guidance names authoritativeness as one of four qualities its ranking systems try to identify, but says “E-E-A-T itself isn’t a specific ranking factor” and defines no separate brand-wide score, so a claim that a recognizable brand outranks by default is a practitioner belief, not a documented Google factor.

AI search and GEO

Branded keyword

A keyword that includes a business's brand name, trademark or other identifying brand term, rather than a generic description of a product or service. Google Ads Help defines a brand by its logo, trademark, domain, dominant product name or business name, and lets advertisers set brand inclusions or exclusions in a campaign separately from ordinary keyword targeting.

Keyword research and intent

Brand entity

A company or product that a search or AI system recognizes as a distinct real-world “thing,” rather than as a text string to match. Google’s Knowledge Graph, launched in 2012, models “real-world entities and their relationships to one another: things, not strings,” and its Knowledge Graph Search API returns typed results such as Organization or Person; a business that Google recognizes there, or in a knowledge panel, is one sign its systems treat it as a distinct entity rather than a keyword.

AI search and GEO

Brand mention

An unlinked reference to a company, product or publication by name, in a blog post, forum thread, video or another piece of web content. Google says its generative AI features “can show what’s being said about products and services across the web, including in blogs, videos, and forum discussions,” while warning that “seeking inauthentic mentions” to influence those results isn’t as effective as it might seem.

AI search and GEO

Breadcrumb Fading · 36%

A row of links near the top of a page showing the page’s place in the site’s hierarchy, or the path a visitor took to reach it. Google reads schema.org BreadcrumbList markup in the page body and uses it to categorize the page’s content for a given search query, and recommends the trail follow a typical user path rather than mirror the URL structure.

First seen 2007 · Peaked 2014 · Retains 36% of peak Technical SEO

Brick-and-mortar In use · 72%

A business that operates from a physical location customers can visit in person, as distinct from an online-only or service-area business. Google Business Profile guidelines call this a storefront business, one of two eligible profile types alongside the service-area business that travels to customers instead, and require permanent signage.

First seen 2005 · Peaked 2014 · Retains 72% of peak Local SEO

Broken link Fading · 32%

A hyperlink whose target no longer returns the page a reader expects, typically because the URL errors out or the destination has been removed. RFC 9110, the HTTP standard, separates two cases: a 404 status means the server found no current resource at that address, while a 410 means the resource is intentionally and probably permanently unavailable.

First seen 2004 · Peaked 2013 · Retains 32% of peak Links and authority Technical SEO audit →

Browser agent

An AI agent that operates a web browser on a person’s behalf, reading and clicking through pages to complete a task instead of a human doing so. Google’s guide to generative AI search says browser agents may access a website by “analyzing visual renderings (like screenshots), inspecting the DOM structure, and interpreting the accessibility tree” rather than viewing the page as a person does, so a site’s technical clarity affects an agent’s ability to act on it.

AI search and GEO

Bulk upload

A spreadsheet-based process for creating or updating many business locations' listings at once, instead of entering each one by hand. Google lets businesses with 10 or more locations verify and manage them from one spreadsheet; Microsoft's Bing Places offers a similar bulk upload tool for businesses adding more than one location.

Local SEO

Business directory

A website that lists businesses by category and location so visitors can browse or search for one, such as a chamber of commerce site or an online Yellow Pages. Google says it compiles Google Business Profile details partly from crawled web content and licensed third-party data; practitioners submit listings to directories as a form of citation building, though Google's local ranking guidance doesn't name directories as a ranking factor.

Local SEO

Business name Current · 95%

The identifying label a business shows on its Google Business Profile and other local listings, which must match the name it actually uses on signage and branding. Google's guidelines bar adding a marketing tagline, store code, phone number or service description to the name — for example, "Verizon Wireless 4G LTE" must be shortened to "Verizon Wireless."

First seen 2005 · Peaked 2023 · Retains 95% of peak Local SEO

Business name keyword stuffing

A manipulation tactic that adds a location, service or product description to a business's name on a listing to rank for more searches, which Google Business Profile guidelines prohibit. Google's guidelines list examples such as "Best Buy Mobile" instead of "Best Buy" and "Midas Auto Service Experts" instead of "Midas," and say violations can lead to Business Profile suspension.

Local SEO

C

Call to action In use · 80%

Text, a button or an image on a page that tells a visitor exactly what to do next, such as “buy now” or “sign up.” Google’s own guidance on website testing uses the same term, citing “Add to cart” against “Buy now!” as an example of call-to-action wording that can swing how visitors act on a page. Google Ads similarly recommends specific, direct calls to action over generic ones in ad copy.

First seen 2004 · Peaked 2024 · Retains 80% of peak Analytics and rank tracking

Call tracking number

A phone number, often assigned by a third-party service, that a business displays in place of or alongside its main number to measure which marketing channel produced a call. Google Business Profile guidelines require the primary listed number to connect directly to the business and stay under its direct control, though they allow additional phone numbers on Business Profile websites and other local surfaces, and bar premium-rate numbers outright.

Local SEO

Canonical tag In use · 78%

An HTML link element, <link rel="canonical">, placed in a page’s head to name the preferred URL among pages with duplicate or very similar content. RFC 6596 defines the canonical link relation, and an HTTP header can carry it for files such as PDFs. Google treats the element as a strong signal and calls any canonical preference “a hint, not a rule,” so Google may choose another URL.

First seen 2009 · Peaked 2015 · Retains 78% of peak Technical SEO

Canonical URL

The URL a search engine picks as the representative version of a page from a set of duplicate or near-duplicate URLs. Google crawls the canonical page most often and judges content and quality mainly from it; HTTPS, redirects, sitemap inclusion and rel="canonical" annotations all feed its choice, and it calls a site’s stated preference “a hint, not a rule.” When content moves, Bing’s Webmaster Guidelines say to use “redirects instead of canonical tags.”

Technical SEO

Case sensitivity Fading · 59%

The treatment of uppercase and lowercase letters as different characters, so that two URLs differing only in letter case can point to different resources. RFC 9110 says a URL’s scheme and host ignore letter case and are normally written in lowercase, but every other component compares case-sensitively; Google’s URL structure guidance gives /APPLE and /apple as an example of two URLs it treats as separate pages with separate content.

First seen 2006 · Peaked 2010 · Retains 59% of peak Technical SEO

CCBot

The web crawler that Common Crawl, a non-profit foundation, uses to build a free, public archive of web pages widely used to train large language models. Common Crawl says disallowing CCBot in robots.txt prevents it from crawling a site; CCBot identifies itself as “CCBot/2.0,” and because other crawlers falsely claim that name, Common Crawl publishes its IP ranges so site owners can verify genuine requests.

AI search and GEO

Centroid

The single geographic point — typically the geometric center of an area's boundary — that a mapping system uses to represent a region as one location. Google's Geocoding API labels a result "GEOMETRIC_CENTER" when it returns this kind of point for a street or an area instead of a precise rooftop address; practitioners use "centroid" for the same reference point when discussing how a search engine measures distance to a searcher.

Local SEO

Chain-of-thought Current · 100%

A prompting and reasoning technique in which a language model produces intermediate reasoning steps before its final answer, instead of jumping straight to a conclusion. A 2022 paper, “Chain-of-Thought Prompting Elicits Reasoning in Large Language Models” (Wei et al.), showed that prompting a large language model with a handful of worked examples containing step-by-step reasoning measurably improved its accuracy on arithmetic, commonsense and symbolic-reasoning tasks; some current models now generate this kind of reasoning by default.

First seen 2022 · Peaked 2026 · Retains 100% of peak AI search and GEO

Chatbot Current · 100%

Software that simulates a text or voice conversation with a person, ranging from simple rule-based scripts to AI systems built on large language models. Google Analytics groups traffic that AI chatbots such as ChatGPT, Gemini, DeepSeek, Copilot or Grok send to a site under a default “AI Assistant” channel, which it defines separately from Google’s own AI Overviews and AI Mode traffic.

First seen 2004 · Peaked 2026 · Retains 100% of peak AI search and GEO

ChatGPT Current · 100%

OpenAI’s conversational AI assistant, reached through a chat interface, that generates text responses and can browse or search the live web for current information. OpenAI’s crawler documentation says ChatGPT fetches a page with the ChatGPT-User agent when a person asks it a question, and surfaces sites in “ChatGPT’s search features” through a separate OAI-SearchBot crawl; a robots.txt rule for OAI-SearchBot governs search, but robots.txt rules may not apply to ChatGPT-User.

First seen 2022 · Peaked 2026 · Retains 100% of peak AI search and GEO

ChatGPT search

OpenAI’s web search feature inside ChatGPT that fetches and cites live pages to help answer a query, instead of relying only on the model’s trained knowledge. OpenAI says its OAI-SearchBot crawler “is used to surface websites in search results in ChatGPT’s search features,” and that a site opted out of OAI-SearchBot “will not be shown in ChatGPT search answers, though can still appear as navigational links.”

AI search and GEO

ChatGPT-User

The user agent OpenAI uses to fetch a web page when a person asks ChatGPT or a Custom GPT a question, rather than to crawl the web automatically. OpenAI says robots.txt rules may not apply to ChatGPT-User because a user starts each request, and that it plays no part in whether content appears in ChatGPT search, which a robots.txt rule for OAI-SearchBot controls.

AI search and GEO

Chrome extension Fading · 26%

A small program, built from HTML, CSS and JavaScript, that users install in the Chrome browser to add a feature or change how it behaves. Google’s developer documentation says “Chrome extensions enhance the browsing experience by customizing the user interface, observing browser events, and modifying the web”; every extension is packaged around a required manifest.json file that declares its permissions and behavior.

First seen 2009 · Peaked 2014 · Retains 26% of peak Web fundamentals

Chunking (content)

The practice of splitting a body of text into smaller passages, or “chunks,” so a retrieval system can index, embed and search them individually. Anthropic’s engineering documentation describes breaking a knowledge base into chunks of a few hundred tokens each so a query retrieves only the most relevant ones; Google says its generative AI search features already parse a full page’s nuance and need no manual chunking from site owners.

AI search and GEO

Citation building

The practice of creating or correcting a business's name, address and phone number on directories and other third-party sites to build a consistent set of local citations. Google says it compiles Google Business Profile details partly from crawled web content and licensed third-party data, but its local ranking guidance never names citations as a ranking factor, so any effect on rank is a practitioner belief, not a documented one.

Local SEO

Citation velocity

A practitioner metric for how quickly a brand, page or claim accumulates new citations or mentions across AI answers and the wider web over time. Bing Webmaster Tools’ AI Performance report, which Microsoft announced in public preview on February 10, 2026, counts “Total Citations” shown as sources in AI-generated answers; Google’s Generative AI performance report in Search Console, launched in June 2026 and available to all sites since August 31, 2026, counts impressions of a site’s links in AI Overviews and AI Mode instead.

AI search and GEO

Claiming a listing

The process by which a business's owner or authorized manager takes control of its profile on a platform such as Google Business Profile, Bing Places or Apple Business. Google has an owner search Google Maps for the business, select "Claim this business," then complete a verification option before gaining control of the listing; Google says this costs nothing.

Local SEO

ClaudeBot

The web crawler Anthropic uses to collect public web content that could help train its generative AI models, such as Claude. Anthropic says a robots.txt rule restricting ClaudeBot signals that a site’s future materials should be left out of its AI training datasets; Claude-SearchBot and Claude-User are separate robots with their own rules, and Anthropic’s bots honor the non-standard Crawl-delay extension.

AI search and GEO

Claude-SearchBot

The web crawler Anthropic uses to index web content so that Claude’s search results are more relevant and accurate. Anthropic says disabling Claude-SearchBot in robots.txt stops it from indexing a site’s content for search, which may reduce the site’s visibility and accuracy in users’ search results; ClaudeBot and Claude-User are separate robots with their own rules.

AI search and GEO

Claude-User

The user agent Anthropic uses to fetch a web page when a person asks Claude a question that needs it, rather than crawling the web on its own schedule. Anthropic says disabling Claude-User in robots.txt stops Claude from retrieving a site’s content in response to a user’s query, which may reduce the site’s visibility in user-directed web search; ClaudeBot and Claude-SearchBot are separate robots with their own rules.

AI search and GEO

Clickbait Current · 93%

A headline, thumbnail or description written to provoke a click by exaggerating or withholding what the content actually delivers. YouTube’s spam policies name and ban one version of this, “malicious clickbait”: “using maliciously misleading titles, thumbnails, descriptions, or imagery to trick users into clicking on a video that does not deliver what was promised,” such as advertising a full match while showing only a clip.

First seen 2014 · Peaked 2019 · Retains 93% of peak On-page and content

Click-through rate In use · 61%

The share of times people who saw a search result, ad or listing clicked it, calculated as clicks divided by impressions and usually shown as a percentage. Search Console Help defines CTR the same way for organic results; Google Ads Help says CTR also feeds a keyword’s expected CTR, one part of Ad Rank.

First seen 2004 · Peaked 2010 · Retains 61% of peak Analytics and rank tracking

Cloaking Obsolete · 9%

The practice of showing search engines different content than human visitors see, done to manipulate rankings and mislead users, which Google’s and Bing’s spam policies both prohibit. Google treats inserting text or code only for crawlers, or serving one page to search engines and another to visitors, as cloaking, though a paywall isn’t cloaking if Google can render the same gated content a subscriber sees. Bing’s guidelines separately warn that cloaking undermines trust and visibility across Bing and Copilot.

First seen 2004 · Peaked 2004 · Retains 9% of peak Spam and black hat History of SEO terms on Wikipedia →

Cluster (local results)

An industry name for several nearby businesses shown as one grouped marker on a map, which splits into individual pins as a viewer zooms in. Google Maps Platform's marker-clustering library gives any developer this grouping behavior for large marker sets; its documentation describes the general technique and never mentions the local pack or local finder, so "cluster" in local-results contexts is practitioner usage borrowing the term.

Local SEO

Cohort analysis

A technique that groups users by a shared starting trait, such as the week they first visited, then compares how each group behaves over time. Google Analytics 4’s Cohort exploration tool defines a cohort as users sharing a dimension value, such as acquisition date, then tracks a return criterion, like a later key event, across daily, weekly or monthly periods.

Analytics and rank tracking

Competitor analysis Current · 100%

The practice of studying rival businesses' keywords, content, rankings or ads to find gaps and opportunities for a site's own strategy. In Google Ads, the auction insights report lets an advertiser compare performance against other advertisers bidding in the same auctions and can show a competitor's domain; organic practitioners run the same kind of comparison manually against competitors' rankings and content.

First seen 2016 · Peaked 2026 · Retains 100% of peak Keyword research and intent

Content creation In use · 64%

The process of producing material — articles, video, images or other formats — for publication on a website or other channel. Google suggests evaluating content by asking “Who, How, and Why” it was made, disclosing AI or automation where readers would reasonably expect it, and it calls heavy use of automation to produce content on many topics a warning sign.

First seen 2004 · Peaked 2025 · Retains 64% of peak On-page and content

Content delivery network Current · 100%

A group of servers in different geographic locations that store copies of a website’s content and serve it to visitors from the server nearest them. Because network distance affects latency, a request routed to a nearby CDN server typically returns faster than one sent to a site’s own, possibly distant, origin server, which can shorten load times and Time to First Byte.

First seen 2006 · Peaked 2026 · Retains 100% of peak Page experience

Content licensing deal

An agreement in which a publisher or platform licenses its content to an AI company for model training, live answers, or both. OpenAI’s December 2023 agreement with Axel Springer lets ChatGPT show summaries of, and links to, Axel Springer’s news brands and lets OpenAI train on that content; Google’s February 2024 expanded partnership gave it access to Reddit’s Data API to, in Google’s words, “display, train on, and otherwise use” Reddit content.

AI search and GEO

Content management system Fading · 28%

Software that lets people publish, organize, edit and remove a website’s content, such as text, images, video and audio, without hand-coding each page. Google’s SEO Starter Guide notes that some content management systems handle certain SEO tasks automatically, such as submitting a sitemap or turning a written title into a page’s <title> element; MDN describes the software’s core job as letting users publish and manage content without directly editing code.

First seen 2004 · Peaked 2005 · Retains 28% of peak Web fundamentals

Content marketing Current · 91%

The practice of publishing material, such as guides, videos or tools, useful enough that an audience seeks it out, shares it and links to it on its own merit. Google’s SEO Starter Guide says other sites linking to a site “happens naturally over time,” and that promoting new content speeds its discovery by interested people and search engines, though overdoing promotion can look like manipulation.

First seen 2008 · Peaked 2020 · Retains 91% of peak On-page and content

Content quality Current · 98%

A measure of how well content serves its readers, judged by originality, depth and the expertise or evidence behind it rather than by its match to a query. Google’s guidance on helpful content asks whether a page offers original reporting, research or analysis; whether it’s substantial and comprehensive; and whether it’s written or reviewed by someone who demonstrably knows the topic.

First seen 2005 · Peaked 2011 · Retains 98% of peak On-page and content Periodic Table of SEO →

Content relevance

The degree to which a page’s own content addresses the meaning behind a query, beyond repeating its words, as practitioners judge it when writing or optimizing a page. Google calls a page containing the same keywords as the query “the most basic signal that information is relevant,” and says its algorithms also check whether a page holds other relevant content beyond the keyword, such as pictures or videos.

On-page and content

Content-Type header

An HTTP header that states the media type of the data in a message so the recipient knows how to interpret it. A 2008 Google Search Central blog post says Googlebot reads this header after downloading a file to tell whether it is HTML, an image or another format, and sets the file aside if the type can’t be determined or isn’t one Google indexes.

Technical SEO

Context window In use · 64%

The maximum amount of text, measured in tokens, that a language model can hold as input and output combined during a single exchange, including conversation history. Anthropic’s model comparison page lists a 1-million-token context window for Claude Opus 5.5 and Claude Sonnet 5, and 200,000 tokens for Claude Haiku 4.5; OpenAI’s model catalog documents context-window sizes the same way, alongside a separate maximum-output-token limit for each model.

First seen 2023 · Peaked 2024 · Retains 64% of peak AI search and GEO

Conversational search

Search carried out as a back-and-forth natural-language dialogue, in which a system keeps context from earlier turns so a person can ask follow-up questions. Google positions AI Mode for “queries where further exploration, reasoning, or complex comparisons are needed,” letting people “ask nuanced questions that might have previously taken multiple searches”; Google also offers Business Agent, which it calls “a conversational experience on Google Search that helps customers chat with your brand.”

AI search and GEO

Conversion In use · 77%

An action a business decides is valuable enough to count and measure, such as an online purchase, a form submission or a phone call. Google Ads still calls a tracked, valuable action a conversion; Google Analytics 4 renamed its own version of the concept to “key event” so the Ads term stays reserved for actions imported into an Ads account.

First seen 2004 · Peaked 2015 · Retains 77% of peak Analytics and rank tracking

Conversion rate In use · 75%

The share of sessions, users or visits that produced a conversion, expressed as a percentage. Google Analytics 4’s own dimensions and metrics glossary defines Session key event rate as “the percentage of sessions that converted” and User key event rate the same way per user, calculated as key events divided by sessions or users.

First seen 2004 · Peaked 2015 · Retains 75% of peak Analytics and rank tracking

Conversion rate optimization In use · 67%

The practice of changing a page or flow to raise the share of visitors who complete a conversion, without necessarily changing how much traffic it receives. Practitioners test changes such as page layout, copy or calls to action, commonly through A/B or multivariate testing, and judge results against a site’s conversion rate and other key performance indicators rather than against traffic alone.

First seen 2007 · Peaked 2017 · Retains 67% of peak Analytics and rank tracking

Copilot Current · 100%

Microsoft’s brand of AI assistants, which gives users natural-language access to AI features and connects them with Microsoft’s own apps and data. Microsoft’s Copilot Chat combines large language models with grounding from web data and, in some contexts, organizational data, and Microsoft builds it into Microsoft 365 apps such as Outlook and Teams and into an Edge side-panel experience.

First seen 2023 · Peaked 2026 · Retains 100% of peak AI search and GEO

Core ranking systems

Google’s term for the group of technologies that generate search results for a query, as opposed to systems built for narrower, specific ranking needs. Google’s guide to these systems covers named components such as PageRank, RankBrain and BERT, and says strong site-wide signals don’t make every page from a site rank well, just as weak ones don’t sink every page.

Algorithms and updates

Core update

A broad, significant change to Google’s search algorithms and ranking systems, released several times a year with advance notice on Google’s ranking-updates list. Google says these updates are not aimed at any specific site or page, and likens the effect to refreshing a list of restaurant recommendations: some entries move down because others now fit better, not because they did something wrong.

Algorithms and updates

Core Web Vitals Current · 99%

Google’s three page-experience metrics: Largest Contentful Paint for loading speed, Interaction to Next Paint for responsiveness, and Cumulative Layout Shift for visual stability. Google says its ranking systems use Core Web Vitals and highly recommends achieving good scores; web.dev rates an LCP of 2.5 seconds or less at the 75th percentile of page loads as good. Google says it “always seeks to show the most relevant content, even if the page experience is sub-par.”

First seen 2022 · Peaked 2024 · Retains 99% of peak Page experience Technical SEO audit →

Cost-per-click Fading · 55%

The price an advertiser pays each time someone clicks its ad, and the name of the bidding method that charges per click rather than per impression. Google Ads lets advertisers set a maximum cost-per-click bid, the most they’re willing to pay for a click; the amount actually charged, the actual CPC, is often lower, and Google says CPC pricing “is sometimes known as pay-per-click (PPC).”

First seen 2005 · Peaked 2010 · Retains 55% of peak Search fundamentals

Country code top-level domain

A top-level domain reserved for a specific country or territory, such as .de for Germany or .cn for China, based on ISO 3166 country codes in the IANA root zone. Google treats a ccTLD as a strong signal that a site targets that country, unless it’s a vanity ccTLD, such as .tv or .me, which Google treats as generic instead.

E-commerce and international

Crawlability

A page’s availability to search engine crawlers, meaning robots.txt allows it, no login blocks it and the server answers with a successful HTTP status. Google says it only indexes pages that are public and don’t block Googlebot, and that a page blocked by robots.txt can still appear in results, since Google never crawls it to see a noindex rule.

Technical SEO

Crawl budget

The set of URLs on a hostname that Google is able and willing to crawl, determined by the site’s crawl capacity limit and Google’s crawl demand. Google says crawl budget mainly concerns very large or fast-changing sites; it recommends consolidating duplicate URLs or blocking unimportant ones in robots.txt, not marking them noindex, because Google must still fetch a noindex page to see the rule.

Technical SEO Technical SEO audit →

Crawl capacity limit

Google’s limit on the total time its crawlers spend holding connections open on a site’s server, based on the number of parallel connections and how long they last. Google gives every site the same conservative default, then raises the limit automatically if demand is high and the server stays healthy, or lowers it if response times slow or the server returns 5xx or 429 errors. It is one of crawl budget’s two components, alongside crawl demand.

Technical SEO

Crawl demand

The amount of crawling Google wants to do on a site, judged per crawler from the site’s size, update frequency, quality and relevance compared with other sites. The biggest factor an owner controls is perceived inventory: unwanted duplicate or unimportant URLs waste crawling that could go to pages that matter. Popularity and staleness matter too, and, since capacity is shared across crawlers, high demand from one, such as AdsBot, can leave less for others.

Technical SEO

Crawler In use · 65%

An automated program that fetches web pages by following links, used by services such as search engines to find content to add to an index. RFC 9309, the Internet standard for robots.txt, calls crawlers “automated clients” that search engines use “to recursively traverse links for indexing”; MDN Web Docs adds that a crawler is often called a bot or robot.

First seen 2004 · Peaked 2005 · Retains 65% of peak Search fundamentals

Crawling Fading · 45%

The stage in which an automated program downloads a page’s text, images and other files after discovering its URL, so a search engine can later index it. Google names crawling as the first of three stages — crawling, indexing and serving — in its guide to how Search works, and says its crawler doesn’t visit every discovered page: some are disallowed by robots.txt, others require a login it can’t complete.

First seen 2004 · Peaked 2005 · Retains 45% of peak Search fundamentals

CSS Cascading Style Sheets

A W3C-standardized style sheet language that describes how HTML or XML documents should be presented, controlling elements’ fonts, colors, spacing and layout. W3C’s own CSS overview calls it “a core language of the open web platform,” used for adding style such as fonts, colors and spacing to web documents; MDN says “cascading” refers to the rules that decide which of several conflicting style declarations wins for a given element.

Web fundamentals

Cumulative Layout Shift

A Core Web Vitals metric that scores unexpected shifts in a page’s visible content by multiplying how much of the viewport moved by how far it moved. web.dev rates a score of 0.1 or less at the 75th percentile of page loads as good, more than 0.25 as poor, and anything between as needing improvement; common causes include images or embeds with unknown dimensions and web fonts that render at a different size than their fallback.

Page experience Technical SEO audit →

Curbside

A pickup method in which a customer receives an order at their parked vehicle outside a business rather than going inside, typically arranged after ordering online or by phone. Google Business Profile lets an owner add attributes describing service options to a listing, which Google says can surface the business in searches for places offering them.

Local SEO

Custom field

An optional data field, beyond the standard name, address and phone number, that a listing platform lets an owner fill in to add extra structured details about the business. Google's bulk upload spreadsheet, for example, doesn't require every column to be filled in, and a separate attributes reference spreadsheet lists the optional details a business can add beyond the required fields.

Local SEO

Cybersquatting Fading · 30%

Registering a domain name that is identical or confusingly similar to someone else’s trademark, in bad faith, to profit from it. ICANN’s Uniform Domain-Name Dispute-Resolution Policy names cybersquatting as an example of the “abusive registrations” a trademark owner can challenge through “expedited administrative proceedings” instead of court, and the US Anticybersquatting Consumer Protection Act makes a domain registrant liable on proof of “a bad faith intent to profit” from the mark.

First seen 2004 · Peaked 2006 · Retains 30% of peak Spam and black hat

D

Dark search

An industry name for search activity that standard web analytics can’t attribute to a specific query or engine, most often because no referrer data reaches the destination site. Analytics platforms fall back to labeling this traffic Direct when no referral-source information is available, the same rule Google’s own Analytics documentation gives for direct traffic, so dark search is usually surfaced only by comparing Direct traffic against Search Console’s own query-level data.

Analytics and rank tracking

Data aggregator

A company that collects business information from multiple sources and licenses or distributes it to search engines, apps and other platforms. Google says it compiles Google Business Profile details from sources including licensed third-party data, crawled web content and user contributions.

Local SEO

Data Studio Current · 98%

A no-cost reporting tool from Google that turns data from connected sources into customizable, shareable dashboards and charts. Its drag-and-drop report editor turns connected data into charts, and viewer filters make reports interactive for sharing with a team or publicly.

First seen 2021 · Peaked 2025 · Retains 98% of peak Analytics and rank tracking

Deep learning Current · 100%

A branch of machine learning that trains neural networks with multiple hidden layers, called deep neural networks, to learn patterns directly from large amounts of data. Google positions deep learning under the broader machine-learning umbrella, built on brain-inspired artificial neural networks, and its Machine Learning Glossary defines a deep model — also called a deep neural network — as one containing more than one hidden layer.

First seen 2013 · Peaked 2026 · Retains 100% of peak AI search and GEO

Deep web Fading · 29%

Web content that standard search engines don’t crawl or index, such as pages behind a login, paywall or search form. Google’s guide to how Search works says indexing isn’t guaranteed and that some pages aren’t accessible to its crawler without logging in; practitioners use “deep web” for this uncrawled content, as distinct from a site’s indexed, or “surface,” pages.

First seen 2004 · Peaked 2005 · Retains 29% of peak Search fundamentals

Direct traffic

Visits that analytics platforms can’t credit to a search engine, referring link or campaign, typically because someone typed or bookmarked the URL directly. Google Analytics 4 assigns the Direct channel to visits via a saved link or typed URL, and its documentation says a session is also processed as direct traffic whenever no referral-source information is available or the referring source has been configured to be ignored.

Analytics and rank tracking

Disavow

A Google Search Console feature that lets a site owner ask Google to disregard specific backlinks when it evaluates the site. Google says to try to get unnatural links removed first and calls disavowing “an advanced feature” for links an owner can’t get removed, warning it can take Google a few weeks to recrawl the web and reprocess a submitted list.

Links and authority

DMCA Digital Millennium Copyright Act

A 1998 US law that lets copyright owners request takedown of infringing material from online services and shields cooperating services from liability for their users’ infringement. The US Copyright Office says its Section 512 notice-and-takedown system lets a rightsholder notify a service provider of infringing material, which the provider must then “act expeditiously to remove or disable,” while Google says it is “Google’s policy to comply with notices of copyright infringement pursuant to” the DMCA.

Spam and black hat

DMOZ In use · 70%

A volunteer-edited directory that organized websites into browsable categories until it closed in 2017. DMOZ said it was built by a global community of volunteer editors, that submitting a site or using its data cost nothing, and that its data fed search engines and portals including AOL Search and Google.

First seen 2004 · Peaked 2014 · Retains 70% of peak Links and authority

Dofollow link

Industry shorthand for a hyperlink carrying no nofollow, sponsored or ugc attribute, leaving a search engine free to weigh it as an ordinary link. Google’s own documentation names nofollow, sponsored and ugc as link attribute values to add, but defines no corresponding “dofollow” attribute; a dofollow link is simply the default state of a link once none of those values are present.

Links and authority

Domain Authority In use · 79%

Moz’s proprietary score, from 1 to 100, that uses machine learning on a domain’s backlink data to estimate its likely ranking strength on Google. Moz calculates DA from the link index its crawler, Dotbot, builds, and says a site’s score changes only when Moz finds new links to it; Page Authority is Moz’s page-level counterpart on the same 1-to-100 scale.

First seen 2015 · Peaked 2016 · Retains 79% of peak Links and authority

Domain name

A sequence of labels, separated by dots, that names a location in the Domain Name System’s tree-shaped namespace, from the most specific label to the top-level domain. RFC 1035 limits each label to 63 octets and a complete domain name to 255 octets, and RFC 1034 has domain names read left to right, from most specific to least specific, ending at the root.

Web fundamentals

Domain Name System

The hierarchical, distributed system, specified in RFC 1034 and RFC 1035, that maps domain names to the numeric addresses and other records associated with them. A DNS lookup resolves a name such as mozilla.org to a numeric IP address, and a reverse lookup does the inverse; Google recommends a reverse DNS lookup of a crawler’s source IP, alongside its published IP ranges, as the reliable way to confirm a request actually came from Googlebot.

Web fundamentals

Domain Rating

Ahrefs’s proprietary score, on a 100-point scale, showing the strength of a website’s backlink profile relative to other domains in its index. Ahrefs spreads each linking domain’s rating across the domains it links to, so a link from a site that links out sparingly counts for more, and calls DR relative: a site’s score can fall without losing links when other sites gain them.

Links and authority

Doorway pages Obsolete · 10%

Sites or pages built to rank for narrow, similar search queries and funnel visitors toward intermediate pages less useful than the destination; Google’s spam policies call this doorway abuse. Examples Google names include running multiple near-identical sites or pages aimed at different cities or regions that all funnel to one page, and building pages that sit closer to search results than a site’s own clearly defined, browsable hierarchy.

First seen 2004 · Peaked 2004 · Retains 10% of peak Spam and black hat History of SEO terms on Wikipedia →

Driving directions Fading · 38%

A calculated route and estimated travel time by car between two points, one of the transportation modes a mapping service offers alongside walking, cycling and transit. Google Maps highlights the best available route in blue when more than one option exists, shows an estimated travel time for each, and offers driving as one mode alongside transit, walking, cycling and flight.

First seen 2004 · Peaked 2007 · Retains 38% of peak Local SEO

Duplicate content In use · 75%

Identical or very similar content that appears at more than one URL, whether on one site or across different sites. Google calls picking one representative page from a set of duplicates canonicalization; it crawls the canonical page most often and the others less, and says some duplication is normal and not a spam violation, though spreading the same content across many URLs can confuse users and dilute how its performance is tracked.

First seen 2006 · Peaked 2012 · Retains 75% of peak Technical SEO

Duplicate listing

A second profile for a business that already has one on the same platform, which Google's policies prohibit because it can mislead customers. Google says a profile may be marked a duplicate because a verified profile for the same business already exists, because it shares an address with another profile, or because separate profiles offer different services for the same business; a duplicate won't show on Search or Maps.

Local SEO

Dwell time Current · 100%

The interval between a searcher clicking a result and returning to the search results, a signal Bing’s Duane Forrester wrote about in 2011 as one it watches for quality. Bing’s Duane Forrester wrote that “a minute or two is good” while “less than a couple of seconds can be viewed as a poor result.” Some practitioners treat dwell time as a Google ranking factor too, but Google’s Gary Illyes called that idea “generally made up crap” in 2019.

First seen 2015 · Peaked 2026 · Retains 100% of peak Analytics and rank tracking

Dynamic content In use · 83%

Page content a server assembles at request time, typically by pulling data from a database into an HTML template, instead of returning an unchanged, pre-built file. MDN Web Docs calls a site built this way a dynamic website, as opposed to a static site that returns the same hard-coded file for every request; search engines see whatever the server (or, for client-rendered pages, JavaScript running in the browser) ultimately produces, not the underlying template or database.

First seen 2004 · Peaked 2007 · Retains 83% of peak Technical SEO

Dynamic URL

A URL generated at request time from parameters, such as a database query, filter or session ID, rather than pointing straight to a fixed file. Google’s URL structure guidance warns that dynamic URLs built from additive filters, session IDs or an unbounded calendar can multiply into huge numbers of near-duplicate pages, wasting crawl budget, and recommends blocking the unneeded ones with robots.txt and trimming parameters that don’t change the content.

Technical SEO

E

Ecommerce Obsolete · 21%

The buying and selling of goods or services over the internet, and the general term for an online store or shopping site. Google publishes a dedicated set of best practices for these sites, covering how product data can appear across Search, Images and other Google surfaces, and how site structure and URL design affect crawling.

First seen 2004 · Peaked 2005 · Retains 21% of peak E-commerce and international

Ecommerce local SEO

Local search optimization for an online store that also serves a specific geographic area, such as one offering in-store pickup, local delivery or a physical showroom. Google classifies a retailer with both a storefront and delivery or online orders as a hybrid business, which can show its address, set staffed hours, and also list a service area on its Google Business Profile.

Local SEO

Ecommerce SEO

The SEO practices applied to online stores — product pages, category and faceted navigation, and the structured data that makes listings eligible for shopping rich results. Google’s ecommerce guidance covers this ground directly — sharing product data, structuring URLs and site navigation, and using structured data — without ever using the phrase “ecommerce SEO” itself.

E-commerce and international

Editorial link

A link that another site’s editor adds on their own judgment because the destination is useful to readers, not because of payment or a submission form. Google tells site owners to qualify a link with sponsored or nofollow if they were paid for it, and with ugc or nofollow where users can insert links, as in forums; practitioners treat a link carrying neither as the site’s own editorial choice.

Links and authority

Editorial summary

A short phrase Google's own writers compose to summarize a business on Google Maps, distinct from the description a business writes about itself. Google says these summaries can appear on the map or beside review and rating information, and unlike a business description, an owner cannot edit or request one.

Local SEO

E-E-A-T experience, expertise, authoritativeness and trustworthiness

A set of four content qualities — experience, expertise, authoritativeness and trustworthiness — that Google’s ranking systems try to identify and its quality raters are trained to assess. Google says E-E-A-T “isn’t a specific ranking factor,” that trust matters most, and that its systems give extra weight to strong E-E-A-T on Your Money or Your Life topics; rater data is not used directly in rankings.

On-page and content

Embedding Current · 100%

A list of floating-point numbers that represents a piece of text, image or other data as a point in a multi-dimensional space, placing similar inputs close together. OpenAI’s embeddings API returns such a vector for a text string and measures the distance between two vectors as their relatedness, and Google’s Machine Learning Glossary similarly defines an embedding vector as numbers trained to capture an input’s meaning.

First seen 2017 · Peaked 2026 · Retains 100% of peak AI search and GEO

Engagement metrics Current · 100%

The group of analytics measures, such as engaged sessions, engagement rate and average engagement time, that describe how people interact with a site or app beyond simply loading it. Google Analytics 4’s Life cycle collection groups its standard reports by topic, keeping Engagement separate from Acquisition, which instead covers how visitors arrived rather than how they behaved once there.

First seen 2009 · Peaked 2026 · Retains 100% of peak Analytics and rank tracking

Engagement rate

In Google Analytics 4, the percentage of sessions on a site or app that count as engaged. GA4 counts a session as engaged if it lasts 10 seconds or more, includes a key event, or shows 2 or more page or screen views, and excludes first_visit, first_open and session_start events from that count even when they are marked as key events.

Analytics and rank tracking

Enterprise local SEO

Local search optimization for a large brand or chain with many locations, run centrally through bulk tools and shared business groups rather than one profile at a time. When a business group's main owner is verified, Google verifies every eligible profile in the group, and a spreadsheet of 10 or more locations from the same business qualifies for bulk verification instead of verifying each profile individually.

Local SEO Local SEO →

Enterprise SEO

Search engine optimization practiced at the scale of a large organization’s website, typically thousands of pages, multiple teams and templated content. Google’s crawl-budget guidance is aimed at very large or fast-changing sites, and recommends consolidating duplicate URLs and managing crawling deliberately — the technical work that scale requires of enterprise sites.

Search fundamentals

Entity SEO

The practice of publishing content and structured data so that search engines correctly identify and connect the people, places, organizations and things — the entities — a site represents. Google’s Knowledge Graph, launched on May 16, 2012, models “real-world entities and their relationships to one another: things, not strings”; its structured data for an Organization supports a sameAs property giving the URL of a page elsewhere with more information about it, such as a social media profile.

On-page and content

Entrances

In Google Analytics 4, the number of times a session’s first event happened on a specific page or screen. GA4 keeps Entrances (and its counterpart, Exits) as metrics inside free-form explorations rather than standard reports, distinct from the Landing page dimension, which names the page rather than counting visits to it.

Analytics and rank tracking

Evergreen content

Content written to stay accurate and useful regardless of when it’s read, instead of tied to a passing news cycle or a trending event. Google’s Search Quality Rater Guidelines separate “newsy” from “timeless” information intent, and say a query for a well-understood fact, such as when Franklin Roosevelt was born, does not require fresh results — the kind of need evergreen content is written to meet.

On-page and content

Exit rate

The share of visits to a given page that ended there, without the visitor viewing another page in the same session. Google Analytics 4 has no metric with this name; its Entrances and exits page defines only Exits, a count of how often a page was the last one viewed in a session, available in Explore rather than standard reports.

Analytics and rank tracking

Expired domain abuse

Buying an expired domain and repurposing it mainly to manipulate rankings, where the hosted content offers users little to no value and instead trades on the domain’s past reputation. Google gives affiliate content on a former government site, and casino content on a former elementary school’s domain, as examples; it says the practice isn’t accidental, since these domains aren’t meant for visitors to find any way other than through search engines.

Spam and black hat

Explicit location

A place name a searcher types directly into a query, such as "hotels in Dallas," that indicates what the searcher wants regardless of their actual location. Google's Search Quality Rater Guidelines coin the term for this signal and instruct raters to pay close attention to it, since it can match or differ from the searcher's actual location or language locale.

Local SEO

External link In use · 68%

A hyperlink on a page that points to a different website rather than to another page on the same site. Google says using external links “can help establish trustworthiness,” for example by citing sources, and tells site owners to add nofollow only when they don’t trust the destination, not on every external link.

First seen 2004 · Peaked 2012 · Retains 68% of peak Links and authority Free SEO Chrome extension →

F

Faceted navigation

A site feature, common on ecommerce category pages, that lets visitors filter items by attributes such as color or size, usually generating a new URL for each combination. Google warns that the resulting URL combinations can overcrawl a site and slow discovery of new pages, and recommends blocking the parameters in robots.txt or pointing a canonical tag at the unfiltered listing page.

E-commerce and international

Fake reviews Current · 96%

A review that misrepresents a genuine customer experience, including one that's paid for, posted from a fake or duplicate account, or written by someone who never used the business. Google's Maps content policy calls this "fake engagement" and removes it, and the FTC's Consumer Reviews and Testimonials Rule, in effect since October 21, 2024, makes it illegal for a business to write or sell a review that misrepresents whether the reviewer exists or had experience with the business.

First seen 2012 · Peaked 2024 · Retains 96% of peak Local SEO

Favicon Obsolete · 24%

The small icon associated with a site that Google can show next to its listing in Search results, set with a link tag in the page’s HTML head. Google reads the icon, apple-touch-icon or apple-touch-icon-precomposed rel attribute, requires a stable square of at least 8x8 pixels, and won’t show a favicon it deems inappropriate, such as pornography or hate symbols.

First seen 2004 · Peaked 2004 · Retains 24% of peak SERP features

Featured snippet Current · 98%

A search result where Google reverses the normal order and shows the descriptive snippet first, pulled from a page its systems judge answers the query well. A featured snippet can appear inside a People Also Ask group; Google says a site owner can’t mark a page as one, since its systems elevate a page automatically, and a lower max-snippet or a nosnippet rule can opt a page out.

First seen 2020 · Peaked 2025 · Retains 98% of peak SERP features

Fine-tuning Current · 98%

A second training pass on an already pre-trained AI model that adjusts its parameters using a smaller, task-specific set of examples. Google’s Machine Learning Glossary describes fine-tuning as refining a pre-trained model’s parameters for a specific use case, and OpenAI documents sending a base model the kinds of inputs and outputs an application expects so it excels at that task.

First seen 2023 · Peaked 2025 · Retains 98% of peak AI search and GEO

First-party review

A customer review collected and published directly on a business's own website or app, rather than on an independent third-party platform. Google's review-snippet structured data guidelines restrict its Local business and Organization review markup to sites that capture reviews about other businesses, so a first-party review on a business's own site isn't eligible for that rich result even when marked up.

Local SEO

Flesch Reading Ease

A readability formula that scores English text on a 0-to-100 scale from its average sentence length and average syllables per word. Microsoft’s implementation in Word states the formula as 206.835 minus 1.015 times average sentence length minus 84.6 times average syllables per word, and says a higher score means the text is easier to read, with most standard documents aimed at 60 to 70.

On-page and content

Forum Fading · 38%

An online space, usually organized into threads, where members post questions or discussion and reply to one another over time. Google’s Discussion forum structured data documentation says DiscussionForumPosting markup helps Google Search “better identify online discussions across the web” and can enable features such as Discussions and Forums, whether a forum’s replies nest under each other or run in a flat, linear thread.

First seen 2004 · Peaked 2004 · Retains 38% of peak Web fundamentals

Frames and framesets

A pair of obsolete HTML elements — <frameset>, which divides a browser window into independently scrolling panes, and <frame>, which loads a separate document into each pane. The HTML Standard lists frame, frameset and noframes as entirely obsolete and says authors must not use them, directing them to iframe and CSS instead; MDN Web Docs marks both as deprecated, noting the lack of accessibility for screen-reader users as one reason modern sites avoid them.

Technical SEO

Freshness

A measure of how recently a page’s content was created or updated, which Google’s raters weigh when judging how well a result meets a searcher’s needs. Google’s Search Quality Rater Guidelines name breaking-news, recurring-event, current-information and product queries as needing recent content, and tell raters to mark a page that lacks it “stale” and give it a low Needs Met rating — though they say freshness matters less for Page Quality rating, where even a stale page can rate highly.

On-page and content

G

Gemini Current · 100%

Google’s family of multimodal AI models and the conversational assistant built on them, used in Google Search, the Gemini app and Google’s developer platforms. Google introduced Gemini in December 2023 as a model designed from the start to work natively across text, code, audio, image and video, and Google’s Machine Learning Glossary cites Gemini as an example of a large language model.

First seen 2023 · Peaked 2026 · Retains 100% of peak AI search and GEO

Generative AI

A category of machine-learning model that generates new material, such as text, images, audio or code, by applying patterns it learned from training examples. Google’s Search Quality Rater Guidelines introduce this definition to help raters judge webpages, and note that generative AI tools can be used to create both high-quality and low-quality content depending on the effort and originality involved.

AI search and GEO

Generative AI search

Search in which a generative AI model writes a response from retrieved web pages rather than just returning ranked links, as Google’s AI Overviews and AI Mode do. Google’s guide says its own generative AI search features rest on its core Search ranking systems, using retrieval-augmented generation, which it also calls grounding, and query fan-out to pull relevant pages from its Search index.

AI search and GEO

Generative engine optimization

The practice of adapting web content so that generative AI search systems cite it or draw on it when composing answers. The term was introduced in a paper first posted to arXiv in November 2023 by Pranjal Aggarwal and five co-authors. Google’s guidance says that, as Google sees it, optimizing for generative AI search “is optimizing for the search experience, and thus still SEO.”

AI search and GEO AI search optimization →

Generative pre-trained transformer Current · 100%

A neural-network architecture that OpenAI introduced in 2018, pre-trained on unlabeled text and then adapted to specific language tasks through fine-tuning. OpenAI’s 2018 paper trained the model on a broad body of unlabeled text before fine-tuning it for individual tasks, reporting gains over prior state-of-the-art systems on 9 of the 12 language benchmarks it tested; later GPT versions scaled up the same recipe.

First seen 2019 · Peaked 2026 · Retains 100% of peak AI search and GEO

Geocoding In use · 74%

The process of converting a written address into geographic coordinates, or the reverse, converting coordinates into a readable address. Google's Geocoding API performs both directions and can also convert a place ID to or from an address; local SEO relies on the coordinates it produces to calculate how far a business sits from a searcher.

First seen 2005 · Peaked 2005 · Retains 74% of peak Local SEO

Geo Data Upload

A discontinued Google tool and file format for submitting a business location's geographic data, referenced in older "Get on Google" documentation. Google's documentation now points businesses that used it to the Google Maps Content Partners resource instead.

Local SEO

Geofencing

A location-based technique that triggers an action when a mobile device enters or leaves a virtual boundary drawn around a real-world area. Android's location APIs define the fence by a latitude, longitude and radius, and can notify an app when a device enters, exits or lingers inside it; marketers use the trigger to send a nearby offer or ad.

Local SEO

Geo-grid rank tracking

An industry technique for measuring local search visibility by checking a business's local-pack ranking from many simulated searcher locations around it. Google says it ranks local results partly on distance between the searcher and the business, so the same listing can rank differently from one point to another; practitioners plot each point's rank on a map to visualize that spread.

Local SEO

Geolocation

A device or browser's ability to report its real-world geographic position, typically as latitude and longitude, to a website or app. The W3C's Geolocation API specification defines this as access to "geographical location information associated with the hosting device," covering latitude, longitude, altitude, speed and heading, and supports both a one-time position request and continuous monitoring.

Local SEO

Geo-modifier

A word or phrase added to a keyword to signal local intent, either a place name such as "in Denver" or a relative one such as "near me." Google says it uses a searcher's location to show nearby results even when a query names no place, but practitioners add a geo-modifier to a keyword when researching or targeting demand tied to a specific place.

Local SEO

Geotagging Fading · 40%

The practice of attaching geographic coordinates to a photo, video or other file, usually as metadata recorded automatically by a camera or phone. Google Photos reads this location data to let a user organize, search and explore photos by where they were taken, though a location a camera embedded automatically can't be edited or removed inside Google Photos.

First seen 2005 · Peaked 2005 · Retains 40% of peak Local SEO

Geotargeting Current · 90%

The practice of showing different content, ads or rankings to a user based on their detected geographic location. Google Ads lets an advertiser target people physically in, regularly in, or merely interested in a location, determined mainly from a device's IP address, and Google Search uses a searcher's location to show nearby results even when a query names no place.

First seen 2010 · Peaked 2021 · Retains 90% of peak Local SEO Local SEO →

Google-Agent

The fetcher that AI agents hosted on Google’s own infrastructure use to browse the web and carry out actions a user has requested. Google lists Google-Agent among its user-triggered fetchers, which it says generally ignore robots.txt rules because a user requested the fetch; its requests come from the IP ranges Google lists in user-triggered-agents.json, and Google is experimenting with the Web Bot Auth protocol to authenticate them.

AI search and GEO

Google Alerts

A free Google service that emails a user new web and news results matching a search topic they choose. Google’s support pages say a user can tune how often alerts arrive, which source types and languages to include, and that Google Alerts sends an email whenever it finds a new matching result.

Analytics and rank tracking

Google Analytics In use · 77%

A free platform from Google that collects data from a website or app through a JavaScript tracking code to build reports on visitors and their behavior. A tracking code collects pseudonymous data on each visit, such as which pages a user visited and their browser type, which Google Analytics turns into reports; Google Analytics 4 is the current version, replacing the earlier Universal Analytics architecture.

First seen 2005 · Peaked 2012 · Retains 77% of peak Analytics and rank tracking

Google Analytics 4

The current version of Google Analytics, an event-based analytics property type that replaced the earlier session-based Universal Analytics architecture. GA4 collects event-based data from both websites and apps and adds privacy controls such as cookieless measurement, instead of the session-based model Universal Analytics used.

Analytics and rank tracking

Google autocomplete In use · 61%

A Google Search feature that predicts and completes a query as a person types it, built from real searches other people have made. Google’s systems weigh the query’s language, the searcher’s location, trending interest and the person’s own past searches, and route predictions through policies that block predictions that are dangerous, hateful, sexually explicit or otherwise policy-violating.

First seen 2004 · Peaked 2017 · Retains 61% of peak SERP features

Googlebot Fading · 58%

The generic name for the two web crawlers Google Search uses — Googlebot Smartphone and Googlebot Desktop — which share one robots.txt user-agent token. Google indexes the mobile version of most sites, so most Googlebot requests use the smartphone crawler; Googlebot fetches only the first 2MB of a page (64MB for a PDF) and discovers new URLs mainly by following links, and Google recommends verifying a request with a reverse DNS lookup or its published IP ranges, since the Googlebot user-agent string is often spoofed.

First seen 2004 · Peaked 2008 · Retains 58% of peak Technical SEO

Google Business Profile Current · 95%

A free business listing that Google shows on Search and Maps, which the owner can claim, verify and edit to manage details such as address, hours and category. Google uses profile information to surface local results, which it ranks mainly on relevance, distance and popularity, and compiles profiles from owner edits, user contributions, crawled web content and licensed third-party data.

First seen 2021 · Peaked 2023 · Retains 95% of peak Local SEO Local SEO →

Google Business Profile attributes

Optional details on a Google Business Profile, such as outdoor seating or Wi-Fi, that tell customers more about what a business offers. Google says attributes show up on Search, Maps and other Google platforms, and adding certain ones can surface a business in searches for places with those attributes; some are owner-edited while others are populated from visitor input.

Local SEO

Google Business Profile category

A classification, chosen from Google's fixed list, that states what a business does and connects it to customers searching for that type of product or service. Google says the categories chosen affect local ranking, lets an owner pick one primary category plus additional ones for departments or services, and doesn't let a business create its own category outside the provided list.

Local SEO Local SEO →

Google Business Profile chat

A Google Business Profile feature that lets a verified business add a text or WhatsApp option so customers can message it directly from Search or Maps. Google's own help documentation calls this feature "Chat"; a business adds the WhatsApp or text option to its Business Profile contact info to turn it on.

Local SEO

Google Business Profile description

A short, owner-written paragraph on a Google Business Profile that tells customers what a business does and what makes it distinct. Google lets an owner write the text directly or generate a draft with an AI feature that pulls from the profile and other sources; Google says the draft should be reviewed for accuracy before saving.

Local SEO

Google Business Profile insights

Data-driven recommendations Google generates on a Google Business Profile to help an owner improve it, drawn from public information such as reviews, photos and local search trends. Google's Business Profile interface currently uses "Performance" for a separate report of views, searches and calls, and separately still uses "Insights" for this recommendations feature, which may not be available on every profile.

Local SEO

Google Business Profile menu

A feature on a Google Business Profile that lets a food or drink business list its menu items, with descriptions, prices and sections, for customers to browse. Google says changes made in the menu editor can take 24 to 48 hours to appear on Maps and Search, and a business already receiving its menu through the Business Profile API may not have this manual editor.

Local SEO

Google Business Profile photos

Photos and videos that an owner adds to a Google Business Profile to help the listing appear more complete and attractive to customers. Google says photos and videos show up on Search and Maps only once the profile is verified, and an owner can set a cover photo and a logo.

Local SEO

Google Business Profile posts

Short updates a business publishes to its Google Business Profile to share announcements, offers or events directly with customers on Search and Maps. Google offers three post types — updates, offers and events — each with a photo or video and an optional action button, and shows them in the profile's "From the owner" section or Updates tab.

Local SEO

Google Business Profile products

A Google Business Profile feature that lets a local store upload images of products it sells, for display in the profile on Google Search. Google designs this product editor for items that lack a barcode or a live stock feed; submissions must follow Google's shopping ads policy, and a business already linked to Google Merchant Center manages products there instead.

Local SEO

Google Business Profile Q&A

A Google Business Profile feature, available only in select categories and regions, where the public can post questions and anyone, including the owner, can post an answer. A question can collect upvotes and multiple answers, sorted with the top answer first.

Local SEO

Google Business Profile services

A Google Business Profile feature that lets certain business categories, especially service businesses, list the specific services they offer, with prices and descriptions. Google offers suggested services tailored to a business's category, such as "Install faucet" for a plumber, and also lets an owner add custom services, which Google automatically rejects if they contain profanity, prices or contact details.

Local SEO

Google Business Profile suspension

Google's removal of a Google Business Profile from Search and Maps for not following its guidelines, which an owner can contest through an appeal. Google's appeal tool asks for evidence such as a business license or a utility bill, which must be submitted within 60 minutes of opening the form, and Google warns against creating a new profile for the same business while an appeal is under review.

Local SEO

Google Business Profile verification

The process of proving ownership or management of a business to Google, which grants control over its Google Business Profile and the ability to edit it. Google verifies a business by mail, phone, email, or a live or recorded video, and the method offered depends on the business's type, public info, region or hours; only a verified profile can be edited or interact with customers.

Local SEO Local SEO →

Google cache

A retired Google Search feature: a cached link, shown in search results and controlled by the noarchive rule, and a related cache: search operator. Site owners no longer need to remove the noarchive meta tag some pages still carry, since other search engines and services may still use it.

SERP features

Google CID

A numeric identifier for a specific place that appears in some Google Maps and Search URLs, distinct from Google's own documented Place ID. Google's own Maps URL documentation shows a "cid" parameter in an example link that opens a place directly, such as maps.google.com/?cid=…, but does not explain what the letters stand for or how the number is assigned.

Local SEO

Google-CloudVertexBot

The web crawler Google uses to fetch pages that a site’s owner has asked it to crawl for building Vertex AI Agents. Google says robots.txt rules addressed to Google-CloudVertexBot affect only these owner-requested crawls and have no effect on Google Search or Google’s other products.

AI search and GEO

Google Discover

A part of Google Search, separate from search results, that shows people content related to their interests based on their Web and App Activity. Content becomes automatically eligible once Google indexes it and it meets Discover’s content policies — no special tags or markup are required — though eligibility never guarantees appearance.

SERP features

Google-Extended

A robots.txt product token that lets a website control whether Google may use its crawled content to train future Gemini models or to ground their answers. Google says Google-Extended has no dedicated HTTP user-agent string of its own, covers both Gemini Apps and the Vertex AI API for Gemini, and does not affect a site’s inclusion in Search or act as a Search ranking signal.

AI search and GEO AI search optimization →

Google-GeminiNotebook

The fetcher Google uses to retrieve individual web pages that a person has added as sources to a Gemini Notebook project. Google lists the fetcher among its user-triggered fetchers, which generally ignore robots.txt rules because a user requested the fetch; its mobile and desktop user-agent strings both contain the Google-GeminiNotebook token.

AI search and GEO

Google Guaranteed

A badge Google awarded to home-service advertisers on Local Services Ads after they passed its screening and verification process. Google awarded the badge to advertisers who passed background, license, insurance and other checks that vary by category and location.

Local SEO

Google Keyword Planner In use · 70%

A free tool inside Google Ads that suggests keywords related to a business and shows estimated monthly searches and cost data for a chosen location and network. Google says the tool helps build keyword lists for Search campaigns and estimate the searches and cost each keyword might receive, drawing on the same historical search data that also powers its forecasts.

First seen 2007 · Peaked 2018 · Retains 70% of peak Keyword research and intent

Google Map Maker

A free Google tool, active from 2008 to 2017, that let volunteers around the world add and edit map data directly. Volunteers called Map Maker editors added roads, businesses and other places, and that same volunteer community reviewed and moderated contested edits before they published to Google Maps.

Local SEO

Google Maps In use · 71%

Google's mapping and navigation service, on the web and as a mobile app, that shows directions, business listings and real-world imagery. Google Maps offers driving, walking, cycling and transit directions with estimated travel times, shows a business's hours and menu alongside Street View imagery, and lets a user save places, contribute reviews and photos, and download maps for offline use.

First seen 2005 · Peaked 2010 · Retains 71% of peak Local SEO

Google Merchant Center

A free Google tool for uploading and managing product data so those products can appear across Google Search, Maps, YouTube and more. A retailer connects a product feed or online store to a Merchant Center account, and Google can combine that feed data with a site’s own Product structured data — using the feed’s price or availability, for example, when the page markup lacks it.

E-commerce and international

Google Place ID

A textual identifier that Google's Places API and related Maps Platform APIs use to uniquely identify a specific place. Google says the same place ID works across its Places, Geocoding and Routes APIs and recommends it as the most reliable way to reference a location, though a place can have more than one ID and an ID may change over time.

Local SEO

Google review link

A URL, generated from a Google Business Profile, that a customer can open to leave a review for that business. Google lets an owner copy this link from the Business Profile's "Get more reviews" card to share on a receipt, in an email or as a QR code, and treats reviews solicited with an incentive as prohibited fake engagement.

Local SEO

Google sandbox Obsolete · 8%

An industry name for a supposed filter that keeps new websites from ranking well in Google for a period after launch. On Google’s Search Off the Record podcast in 2020, John Mueller said no built-in algorithm holds new sites back: Google’s systems guess where to rank a site they know little about and adjust as signals accumulate, which can look like a delay or a temporary boost.

First seen 2004 · Peaked 2006 · Retains 8% of peak Algorithms and updates

Google Search Essentials Fading · 27%

Google’s published set of technical requirements, spam policies and key best practices that make web content eligible to appear, and perform well, in Google Search. Meeting these requirements doesn’t guarantee Google will crawl, index or serve a page, and Google’s own guidance says most sites already pass the technical requirements without their owners realizing it.

First seen 2005 · Peaked 2008 · Retains 27% of peak Search fundamentals

Google Trends In use · 74%

A free Google tool that shows how a search term's popularity has changed over time and across locations, scaled relative to other searches rather than as raw counts. Google describes Trends data as a random sample of aggregated, anonymized and categorized Search and YouTube queries, normalized by the total searches of its time and location and scaled from 0 to 100.

First seen 2007 · Peaked 2011 · Retains 74% of peak Keyword research and intent

Go-to-client

An industry term for a business that travels to serve customers at their location instead of operating from a storefront customers visit. Google's own term for this business type is a service-area business; Google Business Profile Help tells such businesses to remove their public address and list up to 20 service areas instead of a radius.

Local SEO

GPTBot

The web crawler OpenAI uses to collect content that may go into training its generative AI foundation models. OpenAI reads a robots.txt rule disallowing GPTBot as a request to keep a site’s content out of training; that rule does not affect OAI-SearchBot, which surfaces sites in ChatGPT search, or ChatGPT-User, which fetches pages when users ask.

AI search and GEO

Gray hat SEO

An industry label for SEO tactics that fall between compliant “white hat” methods and guideline-violating “black hat” ones, not clearly one or the other. Google’s framework has no matching middle tier: its Search Essentials sort behavior only into spam policies that can lower a site’s ranking and best practices that raise it, so “gray hat” describes practitioner judgment about how a tactic pushes those boundaries, not a Google-recognized status.

Spam and black hat

Grounding

The practice of basing an AI model’s output on specific retrieved source material, rather than solely on what the model learned during training. Google’s Machine Learning Glossary names retrieval-augmented generation as a common grounding technique, and its Search guidance uses the same term for retrieving pages from the Search index at answer time; Microsoft documents Copilot Chat as combining large language models with grounding from web and organizational data.

AI search and GEO

Guest blogging Fading · 44%

Writing an article for publication on someone else’s site, usually in exchange for a byline and a link back to the author’s own site. Google’s spam policies name “articles, guest posts, or press releases distributed on other sites” among examples of link spam when payment is involved and the links pass ranking credit or use optimized anchor text, though Google says paying for links isn’t a violation once they’re qualified with rel="sponsored" or rel="nofollow".

First seen 2014 · Peaked 2016 · Retains 44% of peak Links and authority

Guidelines for representing your business on Google

Google's policy document that sets the rules for what a business may state on its Google Business Profile, covering its name, address, category and hours. Google enforces these rules to keep local listings accurate, and a violation it finds — such as a stuffed business name or an ineligible address — can lead to content removal or profile suspension.

Local SEO

H

H1 tag

The <h1> HTML element, which marks a page’s top-level heading and holds the highest of the six heading ranks, <h1> through <h6>, that the HTML Standard defines. WHATWG’s HTML Standard says these elements “represent headings for their sections,” from <h1> for a top-level section down to <h6>; Google’s SEO Starter Guide says there’s “no magical, ideal amount of headings” and that heading order doesn’t matter for Search, though semantic order helps screen reader users.

On-page and content Technical SEO audit →

Hallucination Current · 100%

Confident-sounding but factually wrong output that a generative AI model presents as if it were making a true statement about the world. Google’s Machine Learning Glossary illustrates this with a model that claims Barack Obama died in 1865, and notes that “confabulation” is probably the more accurate word even though “hallucination” became popular first; a 2022 survey catalogued the phenomenon’s causes across natural-language generation systems generally.

First seen 2023 · Peaked 2026 · Retains 100% of peak AI search and GEO

Heading tag Fading · 46%

Any of the six HTML heading elements, <h1> through <h6>, that the HTML Standard defines to mark a page’s headings and subheadings in ranked order. The HTML Standard ranks the six levels from <h1> highest to <h6> lowest, each heading for its own section; Google says a page needs no set number of headings, and that keeping them in semantic order is “fantastic for screen readers.”

First seen 2004 · Peaked 2005 · Retains 46% of peak On-page and content Technical SEO audit →

Heatmap

A color-coded visualization of where visitors click, move or scroll on a page, with warmer colors marking areas of heavier activity. Microsoft Clarity, for example, documents click, scroll and area heatmaps built from a color scale in which “red indicates hot areas where users interact more” and “blue indicates cold areas where the users interact the least.”

Analytics and rank tracking

Helpful content system

A Google system, launched in August 2022, that aimed to better surface original content written for people rather than primarily to attract search traffic. Google’s August 2022 post introduced it as the “helpful content update,” an automated, site-wide signal; its ranking systems guide says the system evolved into part of Google’s core ranking systems in March 2024.

Algorithms and updates

Hidden content

Practitioner term for a page toggling material between shown and hidden — accordions, tabs, sliders, tooltips — a pattern distinct from hiding text purely to manipulate rankings. Google’s hidden text and link abuse policy explicitly excludes this kind of toggled content, along with screen-reader-only text, because it serves usability rather than deceiving crawlers; the same techniques cross into that policy once they’re used to hide manipulative keywords or links from readers.

Spam and black hat

Hidden text

Text or links placed on a page solely to manipulate search rankings while staying hard for human visitors to see; Google’s spam policies call this hidden text and link abuse. Google names white text on a white background, text hidden behind an image or off-screen with CSS, and zero font size or opacity as violations, but excludes accordions, tabs, sliders, tooltips and screen-reader-only text since these toggle content for usability, not to deceive crawlers.

Spam and black hat

Homepage Fading · 50%

The main page of a website, usually the first page a visitor sees when the site loads and typically reachable from other pages via a “home” or logo link. Google’s Search Quality Rater Guidelines illustrate this with Apple’s and Yahoo’s sites, and list a news site’s homepage as existing mainly to inform users about recent or important events.

First seen 2004 · Peaked 2005 · Retains 50% of peak Web fundamentals

Hostname

The label in a URL’s authority component — a registered domain name or an IP address — that identifies which server a request is addressed to. RFC 3986 defines a URI’s host subcomponent as either a registered name or an IP address literal, and RFC 9110 has clients send it in the Host header, or in HTTP/2 and HTTP/3 the “:authority” field, so a server hosting multiple sites knows which one a request targets.

Web fundamentals

hreflang In use · 60%

An annotation, set with a <link rel="alternate" hreflang="…"> element, an HTTP header or an XML sitemap, that tells Google which pages are other language or regional versions of a page. Google uses the annotations to point searchers to the version that best fits their language or region, but ignores them unless the pages point to each other and doesn’t use them to detect a page’s language; it asks sites using hreflang to name a canonical page in the same language.

First seen 2015 · Peaked 2015 · Retains 60% of peak E-commerce and international Technical SEO audit →

.htaccess

A per-directory configuration file read by the Apache web server that lets a site owner set rules, such as redirects or access controls, without editing the server’s main configuration. Apache’s documentation says a site owner with access to the main server configuration should put rules there instead, since permitting .htaccess files slows the server; Google’s redirects guide names the .htaccess file as one place to set up server-side redirects on Apache.

Technical SEO

HTML Hypertext Markup Language

The markup language, standardized by WHATWG as a Living Standard, used to structure content and applications on the web through a tree of nested elements. Each element is marked up with a start tag and, usually, an end tag, and can carry attributes that change how it behaves; WHATWG publishes the standard as a continuously updated “Living Standard” rather than dated, versioned releases.

Web fundamentals

HTML attribute

A name-value pair, placed inside an element’s start tag, that configures or adds metadata to that HTML element. The HTML Standard says an attribute’s name and value are separated by an “=” character, and that omitting the value entirely, in the “empty attribute syntax,” implies an empty string, as with the disabled attribute in <input disabled>.

Web fundamentals

HTML sitemap Obsolete · 22%

A page on a site, written in ordinary HTML and meant for visitors, that links to the site’s main pages the way a table of contents would. MDN Web Docs says a site map gives users a single-glance overview of a site’s content and gives crawlers links to follow. Google accepts sitemaps in XML, RSS or Atom, and plain-text formats, not HTML, so it reaches an HTML sitemap’s pages by crawling its links like any other page.

First seen 2004 · Peaked 2005 · Retains 22% of peak Technical SEO

HTML tag

The markup, delimited by angle brackets, that opens or closes an HTML element, such as <p> to start a paragraph and </p> to end it. The HTML Standard requires a start tag’s first character to be “<” and its last “>”, with the element’s name in between, and an end tag to add a “/” before that name; some elements, such as void elements, take no end tag at all.

Web fundamentals

HTTP Hypertext Transfer Protocol

The application-level protocol that clients and servers use to exchange request and response messages when transferring hypertext and other resources on the web. RFC 9110 defines HTTP’s semantics independently of any one version — HTTP/1.1, HTTP/2 or HTTP/3 — and covers the “http” and “https” URI schemes, the request methods, and the status codes and header fields every message carries.

Web fundamentals

HTTP header

A name/value pair — called a field in RFC 9110 — sent in an HTTP request or response’s header section to convey information beyond the message’s control data and content. Request headers describe the client or the resource it wants; response headers describe the server or what it’s returning; and Google reads specific ones, such as Content-Type and X-Robots-Tag, as instructions for indexing a file.

Web fundamentals

HTTPS Hypertext Transfer Protocol Secure

A URI scheme, defined in RFC 9110, that identifies a resource reached only over a connection secured with TLS, carrying confidentiality and integrity protection between client and server. RFC 9110 sets TCP port 443 as the https scheme’s default. Google announced in August 2014 that it was beginning to use HTTPS as a lightweight ranking signal, but its current page-experience guidance says such aspects, beyond Core Web Vitals, “don’t directly help your website rank higher in search results.”

Web fundamentals

HTTP status code

A three-digit number, defined in RFC 9110, sent with every HTTP response, whose first digit gives its class: informational, success, redirection, client error or server error. Google’s crawlers follow at most 10 redirect hops by default. Google treats the 4xx codes it documents, except 429, alike: a URL returning one is kept out of Google Search’s index, and Google crawls it less and less often. Google’s crawlers slow down temporarily when a site returns 5xx errors, and Google Search eventually drops indexed URLs that keep returning one.

Technical SEO

Human-in-the-loop

A loosely defined practice of keeping people involved in shaping, evaluating or reviewing an AI system’s output rather than automating a task end-to-end. Google’s Machine Learning Glossary calls this idiom “loosely-defined” and gives a system in which an AI generates code for engineers to review as one example of keeping a human in the loop.

AI search and GEO

Hummingbird Fading · 56%

A rewrite of Google’s core search algorithm, first used in August 2013, designed to weigh the meaning of a whole query rather than matching individual words. Search Engine Land reported that Google revealed the name at a September 26, 2013 press event, saying Hummingbird replaced the prior algorithm while still using existing signals such as PageRank; Google’s current ranking-systems guide lists it among retired systems folded into ongoing evolution.

First seen 2013 · Peaked 2014 · Retains 56% of peak Algorithms and updates

Hyperlink

A connection, encoded in an HTML element such as <a>, between the current document and another resource that a user can follow to navigate there or download it. The WHATWG HTML Standard defines hyperlinks as links “generally exposed to the user by the user agent so that the user can cause the user agent to navigate to those resources,” created mainly through the href attribute on <a> and <area> elements.

Web fundamentals

Hyperlocal Fading · 53%

Marketing or content narrowly targeted to a very small area, such as a neighborhood or a few streets, rather than an entire city or region. Google says it can use a searcher's precise location — "exactly where you are, such as a particular address" — to shape search results, the granularity that hyperlocal targeting depends on.

First seen 2012 · Peaked 2021 · Retains 53% of peak Local SEO

Hypertext Fading · 30%

Text, and the documents built from it, that links to other texts rather than presenting information in one linear sequence. Ted Nelson coined the term in a 1965 paper, writing, “Let me introduce the word ‘hypertext’ to mean a body of written or pictorial material interconnected in such a complex way that it could not conveniently be presented or represented on paper.” The WHATWG HTML Standard calls the link an <a> element creates a “hypertext anchor.”

First seen 2004 · Peaked 2004 · Retains 30% of peak Web fundamentals

I

iframe

An HTML element, <iframe>, that embeds another, independent HTML document inside the current page as a nested browsing context. Each iframe creates its own browsing context with its own document, but its navigations fold into the parent page’s session history instead of forming a separate one. Google’s robots meta tag rules let a page opt back into being indexed when it’s embedded through an iframe elsewhere, using the indexifembedded rule alongside noindex, even though the embedded page itself is excluded from the index on its own.

Technical SEO

Image SEO

The practice of optimizing an image and its surrounding HTML so it can appear in Google’s image results, Discover and other visual search features. Google calls alt text the most important attribute for providing metadata about an image, recommends short but descriptive file names such as my-new-black-kitten.jpg over IMG00023.JPG, and warns that images are often the largest contributor to a page’s overall size.

On-page and content

Impression In use · 80%

A single instance of a link or ad being shown to a user, counted by platforms such as Search Console and Google Ads to gauge how often something appeared. Search Console counts one impression each time a link appears in a results set, whether or not it needs scrolling into view, without adding another for scrolling away and back in the same search; Google Ads instead counts a new impression every time an ad is shown on a results page or elsewhere on the Google Network.

First seen 2004 · Peaked 2013 · Retains 80% of peak Analytics and rank tracking Rank tracking →

Indexability

A crawled page’s eligibility for a search engine’s index, meaning it has readable content, no noindex rule and no spam-policy violation. Google lists indexable content as one of three technical requirements for a page to be eligible for its index, alongside an unblocked Googlebot and a working page; meeting them still doesn’t guarantee indexing. Crawlability and indexability differ: a page blocked by robots.txt can still appear in results, since Google never crawls it to see a noindex rule.

Technical SEO Technical SEO audit →

Indexing Fading · 57%

The stage in which a search engine analyzes a crawled page and stores it in a large database, its index, so the page can later be matched to queries. Google’s guide to how Search works says this stage covers text, key tags such as title elements, and canonicalization — grouping duplicate pages and picking one representative version — and that indexing isn’t guaranteed even for pages it has crawled.

First seen 2004 · Peaked 2007 · Retains 57% of peak Search fundamentals

Infographic In use · 64%

A single image that presents information, data or a process visually, typically combining charts, icons and short text. Google says it works out an image’s subject from alt text, computer vision and the page around it, including captions and image titles, and advises placing images near relevant text; it doesn’t index CSS images, so an infographic set as a CSS background won’t be indexed as an image.

First seen 2012 · Peaked 2016 · Retains 64% of peak Links and authority

Informational query

A search query whose purpose is to learn something, the sense Google's Search Quality Rater Guidelines formally define as a Know query. The guidelines describe the intent to find information or explore a topic, and separately name Know Simple queries, a subtype seeking one short, factual answer; the same document also uses the phrase 'informational query' informally elsewhere without defining it as its own category.

Keyword research and intent

Information architecture Obsolete · 14%

The practice of organizing a site’s content, navigation and labeling so that people can find information and complete tasks easily. MDN Web Docs describes it, in web design, as organizing a site’s information, content and functionality so its services are easy to use and find. For crawling, Google says “every page you care about should have a link from at least one other page on your site.”

First seen 2004 · Peaked 2004 · Retains 14% of peak Technical SEO

In-store

A purchase, pickup or visit that happens at a business's physical retail location, as distinct from online, curbside or delivery. Google lets eligible retailers show in-store products on their Google Business Profile so shoppers can see what's in stock, and Merchant Center separately collects in-store product and price availability to power local inventory ads and free local listings.

Local SEO

Interaction to Next Paint

A Core Web Vitals metric that measures responsiveness by timing a page’s clicks, taps and key presses until the browser paints the next frame, then reporting the slowest, ignoring outliers. INP replaced First Input Delay as a Core Web Vital on March 12, 2024. web.dev rates 200 milliseconds or less at the 75th percentile of page loads as good, more than 500 milliseconds as poor, and anything between as needing improvement.

Page experience

Internal link Fading · 58%

A hyperlink that points from one page to another page on the same site. Google says “every page you care about should have a link from at least one other page on your site,” and that there’s no ideal link count: “if you think it’s too much, then it probably is.”

First seen 2004 · Peaked 2008 · Retains 58% of peak Links and authority

International SEO

The practices that help Google serve the right language or regional version of a site to a searcher, such as hreflang annotations and locale-specific URLs. Google’s own guidance splits this into multilingual sites, which offer more than one language, and multi-regional sites, which target specific countries; a site can be both, and Google determines a page’s language from its visible content, not code-level signals.

E-commerce and international

Intrusive interstitials

Page elements such as full-page overlays or pop-up dialogs that obstruct a visitor’s view of the main content, usually to promote something. Google says interstitials cover the whole page and dialogs cover only part of it, and that both can leave Google and other search engines struggling to understand a page’s content, which may lead to poor search performance; Google exempts interstitials that are legally mandatory, such as age checks.

Page experience

Invisible text Obsolete · 0%

An older name for keywords hidden from readers but visible to crawlers, classically as white text on a white background. Google’s spam policies now cover the technique under hidden text and link abuse. Practitioners now treat hidden text as the umbrella term for the policy, with invisible text naming only its original, low-tech form: matching a font’s color to its background so crawlers still read the words.

First seen 2005 · Peaked 2005 · Retains 0% of peak Spam and black hat

IP address

A number, unique within its network, that identifies a device’s location on the internet so data can be routed to it. RFC 791 defines the original IPv4 address as a 32-bit number split into a network part and a host part; RFC 8200 defines IPv6’s separate, 128-bit addresses as its successor.

Web fundamentals

J

JavaScript

A programming language, standardized by Ecma International as ECMAScript (ECMA-262), used to add interactive and dynamic behavior to web pages. Ecma International’s own specification says the standard is “based on several originating technologies, the most well-known being JavaScript (Netscape) and JScript (Microsoft),” and that Brendan Eich invented the language at Netscape, where it first appeared in the Navigator 2.0 browser; Ecma published the 17th edition, ECMAScript 2026, in June 2026.

Web fundamentals

JavaScript SEO

The practice of making JavaScript-rendered pages and web apps crawlable, renderable and indexable by search engines. Google processes JavaScript web apps in three phases — crawling, then rendering with an evergreen version of Chromium, then indexing — and says server-side rendering or pre-rendering is still worthwhile because it makes a site faster and not every bot can run JavaScript. Google recommends setting the canonical URL in the original HTML rather than injecting it only with JavaScript, but explicitly allows JavaScript to set or change the title and meta description.

Technical SEO

JSON-LD JavaScript Object Notation for Linked Data

A JSON-based format, standardized by the W3C, for encoding Linked Data — the format Google recommends for the structured data it uses to power rich results. The W3C published JSON-LD 1.1 as a Recommendation on July 16, 2020; Google says it’s the easiest of the three formats it supports to implement and maintain at scale, since the markup sits in a script tag separate from the page’s visible text.

Structured data and entities

Justifications (local pack)

An industry name for short lines, such as a review or a matched service, that Search Engine Roundtable has reported Google testing under local-pack listings to explain each match. Search Engine Roundtable reported in December 2020 that Google was testing service labels in the local pack, citing Colan Nielsen, who said Google calls such labels, like review and website mentions, "justifications"; in February 2024 it reported Google testing a shaded "people like" version. Google's local ranking help page never uses the word.

Local SEO

K

Key performance indicator Current · 91%

A measure a business tracks over time because it reflects progress toward a specific goal, chosen from many possible metrics available to it. Google Ads Help draws that line for its own Quality Score explicitly, saying the score “is not a key performance indicator” and should not be optimized as though it were a business goal, since it works only as a diagnostic tool.

First seen 2006 · Peaked 2017 · Retains 91% of peak Analytics and rank tracking

Keyword In use · 80%

A word or phrase that content or an advertising campaign is built to target because searchers are expected to type or speak it. Google Ads Help separates the keyword an advertiser selects from the search term a person actually enters, and says match types and search-term similarity decide which searches can trigger a matching ad.

First seen 2004 · Peaked 2017 · Retains 80% of peak Keyword research and intent

Keyword cannibalization

A pattern in which two or more pages on a site target the same or similar keyword and compete against each other in results instead of one page ranking. Practitioners find it the way they check keyword mapping, by filtering Search Console's Performance report to a query and viewing its Pages tab, then consolidating, redirecting or differentiating the competing pages.

Keyword research and intent

Keyword density Obsolete · 21%

The share of a page’s words that match a given keyword or phrase, usually expressed as a percentage. Google’s SEO Starter Guide sets no target: it says repeating the same words “is tiring for users” and that keyword stuffing breaks Google’s spam policies, so a density target in an SEO tool is that tool’s heuristic, not a Google rule.

First seen 2005 · Peaked 2010 · Retains 21% of peak On-page and content

Keyword difficulty

A score that a keyword research tool assigns to estimate how hard it would be to rank a page organically for a given keyword. Google publishes no organic-ranking score under this name, and Keyword Planner's own Competition rating instead measures advertiser bidding, not organic difficulty.

Keyword research and intent

Keyword mapping

The practice of assigning each target keyword, or cluster of related keywords, to one specific page on a site so that page alone is built to rank for it. Practitioners check Search Console's Performance report, filtering to a query and opening its Pages tab, to see which URL currently ranks for a term before deciding where that term belongs.

Keyword research and intent

Keyword research Fading · 45%

The practice of finding and evaluating the words and phrases an audience searches for, to decide which terms a site or campaign should target. Practitioners draw on tools such as Google's own Keyword Planner and Google Trends, which surface search-volume estimates and relative interest over time, to compare demand across candidate terms before writing or bidding on content.

First seen 2007 · Peaked 2009 · Retains 45% of peak Keyword research and intent

Keyword stemming In use · 65%

Treating different grammatical forms of the same word, such as a plural or a verb ending, as equivalent when matching a query to content. Google Ads Help names stemming among the close variants its keyword matching recognizes, giving "floor and flooring" as its example, alongside misspellings, plurals, abbreviations and accents.

First seen 2006 · Peaked 2009 · Retains 65% of peak Keyword research and intent

Keyword stuffing Obsolete · 21%

Filling a page with keywords or numbers, often in unnatural lists outside normal sentences, in an attempt to manipulate a page’s rankings in Google Search. Google gives lists of phone numbers, or blocks of city and region names, without added value as examples, alongside repeating the same phrase until it reads unnaturally; Bing separately warns against “artificially engineered language” that targets ranking systems rather than readers.

First seen 2005 · Peaked 2005 · Retains 21% of peak Spam and black hat History of SEO terms on Wikipedia →

Knowledge Graph Current · 94%

Google’s database of real-world entities — people, places, things — and the relationships between them, which Search draws on to match a query to the right meaning. Google launched it on May 16, 2012, saying it moves Search from matching keyword strings toward understanding “things, not strings”; entities from it can surface in knowledge panels and other Search features.

First seen 2012 · Peaked 2025 · Retains 94% of peak SERP features

Knowledge panel In use · 87%

An information box that Google Search shows for an entity — a person, place, organization or thing — in its Knowledge Graph, summarizing what Google’s systems understand about it. Panels are generated automatically from sources across the web and, for some topics, licensed data partners; the entity a panel describes, or its official representative, can claim the panel and suggest edits.

First seen 2017 · Peaked 2025 · Retains 87% of peak SERP features

L

Landing page In use · 77%

The page a visitor reaches after clicking a search result or an ad. Google’s Search Quality Rater Guidelines use the term strictly: “The Landing Page (LP) is the page you see after you click a link in the result block.” Google Ads Help applies the same idea to paid clicks: “the webpage where people end up after they click your ad,” usually the ad’s final URL.

First seen 2004 · Peaked 2009 · Retains 77% of peak On-page and content

Large language models Current · 98%

A language model built with an especially large number of parameters, or, more loosely, any Transformer-based model designed to generate and understand natural language. Google’s Machine Learning Glossary lists Gemini and GPT as examples of such Transformer-based models, and separately notes that a pre-trained model today usually means a large language model or other generative AI system, first trained on a vast text dataset before any further refinement such as fine-tuning.

First seen 2022 · Peaked 2025 · Retains 98% of peak AI search and GEO

Largest Contentful Paint Current · 98%

A Core Web Vitals metric that times how long a page’s largest image, text block or video within the viewport takes to render after loading starts. web.dev rates 2.5 seconds or less at the 75th percentile of page loads as good, more than 4 seconds as poor, and anything between as needing improvement; the measurement includes redirect time, connection setup and Time to First Byte delays from before the element even starts loading.

First seen 2023 · Peaked 2025 · Retains 98% of peak Page experience Technical SEO audit →

Latitude and longitude Fading · 44%

The coordinate pair — latitude for position north or south, longitude for east or west — that pinpoints an exact location on Earth for maps and location data. The Google Business Profile bulk-upload spreadsheet requires coordinates precise to at least 6 decimal places to place a new listing on Maps, and schema.org's GeoCoordinates type records both values, referenced to the WGS 84 datum, in structured local-business data.

First seen 2004 · Peaked 2005 · Retains 44% of peak Local SEO

Lazy loading Current · 96%

A performance technique that delays loading images, iframes or other non-critical resources until they are about to enter the viewport, instead of loading everything when the page first opens. Browsers support this natively via the loading="lazy" attribute on img and iframe elements. Google warns that scroll- or click-triggered lazy-loading can hide content from Googlebot, since Google Search does not interact with pages, and recommends the native attribute, IntersectionObserver, or a library that loads content once it enters the viewport.

First seen 2014 · Peaked 2024 · Retains 96% of peak Page experience Technical SEO audit →

Lighthouse

An open-source, automated auditing tool, built by Google, that scores a web page on performance, accessibility, best practices and SEO, then lists specific fixes. Lighthouse works as a DevTools panel, a command-line tool, or a Node module that audits any public or authenticated page and produces a report; each failed audit links to guidance on why it matters and how to fix it.

Page experience

Link bait

Content created mainly to attract links and shares, such as original research, a contrarian argument or an interactive tool. Google’s spam policies list “creating low-value content primarily for the purposes of manipulating linking and ranking signals” among examples of link spam.

Links and authority

Link building In use · 79%

The deliberate practice of earning or otherwise obtaining links from other sites, as distinct from links that accumulate simply as a byproduct of publishing. Google’s spam policies prohibit buying or exchanging links for ranking purposes, and list paid guest posts, low-quality directories and automated link creation among the tactics it treats as link spam rather than legitimate promotion.

First seen 2005 · Peaked 2020 · Retains 79% of peak Links and authority

Link exchange Obsolete · 21%

A scheme in which sites agree to link to each other, or join a wider group doing so, mainly to manipulate rankings rather than to help readers. Google’s link spam policy names “excessive link exchanges (‘Link to me and I’ll link to you’)” as an example of link spam, alongside “partner pages exclusively for the sake of cross-linking,” distinct from a link swap that happens naturally between related sites.

First seen 2005 · Peaked 2006 · Retains 21% of peak Spam and black hat

Link farm Obsolete · 22%

A group of low-value websites built mainly to link to each other, or to a target site, and inflate its apparent popularity with search engines. Google does not use the term, but its link spam policy bans this pattern under “using automated programs or services to create links to your site,” among other examples, and can rank a violating site lower or drop it from results.

First seen 2004 · Peaked 2007 · Retains 22% of peak Spam and black hat History of SEO terms on Wikipedia →

Link hub

A page built mainly to organize and link out to a cluster of related pages on one topic, rather than to cover the topic in depth itself. Google says “every page you care about should have a link from at least one other page on your site” and asks for descriptive rather than generic anchor text; a hub supplies both for a whole topic cluster at once.

Links and authority

Link juice Obsolete · 0%

The ranking value that practitioners say a link passes from the page that carries it to the page it points to. The metaphor describes PageRank, in which a page’s score is shared among its outgoing links, so a link from a highly ranked page with few links counts for more. Google says PageRank remains part of its core ranking systems but is one signal among many.

First seen 2015 · Peaked 2015 · Retains 0% of peak Links and authority

Link popularity Fading · 33%

An early search-ranking concept that judged a page by how many other pages linked to it. PageRank refined the idea by weighting each link by the rank of the page it comes from rather than simply counting links; Google says PageRank was one of its core ranking systems at launch and remains part of them today.

First seen 2004 · Peaked 2007 · Retains 33% of peak Links and authority

Link rot Fading · 35%

The gradual buildup of broken links on a site or across the web as linked pages move, change or disappear over time. RFC 9110, the HTTP standard, offers two remedies: a 301 status tells clients a resource has a new permanent address that future references should use, and a 410 says it is intentionally gone and that its owners want remote links to it removed.

First seen 2004 · Peaked 2004 · Retains 35% of peak Links and authority

Link spam In use · 61%

Creating links to or from a site mainly to manipulate its search rankings rather than to help readers find something useful. Google names buying or selling links, excessive reciprocal link exchanges, and automated link-creation programs as examples, though it treats paid links as ordinary web advertising once each one carries a rel="nofollow" or rel="sponsored" attribute.

First seen 2004 · Peaked 2007 · Retains 61% of peak Spam and black hat

Link velocity

The rate at which a site gains, or loses, backlinks over a given period. Practitioners watch it for sudden spikes: Google’s spam policies name “using automated programs or services to create links to your site” as link spam, and Google says looking at all the links it finds helps it “better understand unnatural linking patterns.”

Links and authority

Listing hijacking

The unauthorized takeover of a business's listing on a platform such as Google Business Profile, so someone other than the business controls its information. Google's ownership process lets anyone request access to a claimed profile from its current owner and, if that owner doesn't respond in the 3 days Google allows, claim it outright — the opening practitioners describe as hijacking when a bad-faith requester exploits it.

Local SEO

Listing management

The ongoing task of creating, verifying and keeping current a business's profile on the platforms that show it in local search results. In Google Business Profile, Business Profile Manager lets an account add and manage multiple business locations, and a bulk-upload spreadsheet lets it verify or update several at once instead of claiming each profile by hand.

Local SEO

Listing merge

The process of combining two duplicate profiles for the same business into a single listing on a platform such as Google Business Profile. Google merges incorrectly split profiles on request — a suggestion submitted through Google Maps and subject to review — and says the reviews from both profiles carry over into the surviving one.

Local SEO

LLM optimization Large language model optimization

The practice of shaping content so that large language model assistants, such as ChatGPT, mention, quote or recommend it, whether they answer from training data or a live search. The label spans both routes by which an assistant can learn about a site: OpenAI says GPTBot collects content that may be used to train its models, while OAI-SearchBot surfaces sites in ChatGPT’s search features.

AI search and GEO AI search optimization →

llms.txt

A proposed Markdown file, at /llms.txt or under any subpath, that gives language models and AI agents a short overview of the pages it covers and links to them. Jeremy Howard published the proposal at llmstxt.org in September 2024 and revised it in August 2026. Google says Google Search ignores these files, and the crawler documentation of OpenAI, Anthropic, Perplexity and Apple does not say their crawlers read them.

AI search and GEO AI search optimization → What is llms.txt? →

Local algorithm

An industry name for the ranking system Google uses to decide which businesses appear, and in what order, in local search results. Google says it ranks local results mainly on relevance, distance and popularity, keeps the algorithm's details confidential to keep ranking fair, and offers no way to pay or ask for a better position.

Local SEO

Local business listing In use · 71%

A business's own profile record — name, address, phone number, hours and category — on one platform, such as Google Business Profile, a map app or an online directory. Google says it compiles such records from what an owner submits plus crawled web content, licensed third-party data and user contributions, and that complete, accurate records are more likely to appear in local search results.

First seen 2007 · Peaked 2014 · Retains 71% of peak Local SEO

Local business structured data

Structured data, using schema.org’s LocalBusiness type, that tells Google about a business’s hours, departments and reviews so they can appear in a knowledge panel or business carousel. Google displays this information in local business carousels for category searches and in knowledge panels for a specific business, and the same markup can enable direct booking or ordering through the Maps Booking API.

Structured data and entities

Local citation

An online mention of a local business’s name, address and phone number on a site other than its own, such as a directory listing or a news article. Google says it compiles Google Business Profile details from sources that include crawled web content and licensed third-party data, and bases prominence partly on how many websites link to a business. Its local ranking guidance does not mention citations, so a direct ranking effect is a practitioner belief, not a documented Google factor.

Local SEO Local SEO → What is a local citation? →

Local content

Content written or structured to signal relevance to a specific place, such as a city, neighborhood or service area, rather than to a general audience. Google's helpful-content guidance holds it to the same bar as any other page, whether it genuinely helps the people who find it, and Google's spam policies count pages aimed at particular cities or regions that funnel visitors to one page as doorway abuse.

Local SEO

Local filter

An industry name for the times a Google Business Profile drops out of local results for being marked a duplicate of another profile at the same address. Google restricts multiple profiles at one address to businesses that are distinct, separately named and visibly signed, and marks a profile a duplicate if it shares an address with an existing one — the closest documented mechanism to what practitioners call filtering, though Google publishes no broader rule by that name.

Local SEO

Local finder

An industry name for the fuller list of nearby businesses Google shows after a searcher clicks through from the local pack, beyond the handful shown there. Google Ads Help describes reaching this view as clicking "More places" in the local results; Google says it ranks local results mainly on relevance, distance and popularity, but its current documentation does not use the name "local finder."

Local SEO

Local Guides

A Google program in which individual contributors write reviews, share photos, answer questions and edit place information on Google Maps in exchange for points and program benefits. Google restricts the program to individuals rather than businesses, says contributions from a business account don't count toward Local Guides levels, and strictly prohibits businesses from soliciting Local Guides.

Local SEO

Local keyword research

Keyword research narrowed to search terms with local intent, such as those naming a city, neighborhood or "near me," to find what nearby customers search for. Google Ads' Keyword Planner returns monthly search-volume estimates for keyword ideas generated from a business's own products, services or website — a general-purpose tool practitioners adapt to location-qualified terms rather than a location-specific product.

Local SEO Local SEO →

Local landing page

A page built to rank for and convert searchers in one specific city, neighborhood or service area, usually one of several similar pages built for other areas a business serves. Google's spam policies count pages aimed at particular cities or regions that funnel visitors to one page as doorway abuse, so practitioners write each page to be genuinely distinct rather than a template with the place name swapped.

Local SEO

Local link building

The practice of earning backlinks from sites with genuine local relevance — news outlets, chambers of commerce, sponsorships — to support a business's visibility in local search. Google's spam policies treat exchanging money, goods or services for links, and excessive link exchanges, as link spam whatever a site's local angle, so practitioners pursue links that grow out of a real local relationship.

Local SEO Local SEO →

Local marketing

Marketing aimed at customers in a business's own city or service area, spanning local search, local ads, reviews and other channels rather than one tactic alone. Google Ads offers formats built for this goal, including Performance Max and Maps ad placements, that draw on a business's Google Business Profile locations to reach nearby searchers specifically.

Local SEO

Local pack In use · 82%

A block in Google Search results that lists nearby businesses’ Google Business Profiles for searches with local intent; Google’s own help pages call these “local results.” Google says local results are “mainly based on relevance, distance, and popularity,” uses the searcher’s location even when a query names no place, and says businesses cannot pay for or request a higher local ranking.

First seen 2017 · Peaked 2018 · Retains 82% of peak Local SEO Rank tracking →

Local ranking factors

The inputs that Google names, or that practitioners believe, shape a business's position in local search results, chief among them Google's own three: relevance, distance and popularity. Google defines relevance as how well a profile matches a search and distance as how far the business is from the searcher, and explains the third factor under the heading "Prominence": how well-known a business is, based partly on links and reviews. Google keeps the full system confidential.

Local SEO

Local rank tracking

The practice of repeatedly checking a business's position in local search results, often from several simulated searcher locations around its service area, to measure local pack visibility over time. Google Business Profile's own performance reports show views, the search terms that surfaced a listing, and customer actions, but no ranking position, which is why practitioners built separate tools and methods to approximate one.

Local SEO

Local search In use · 75%

A search for a nearby business, service or place, together with the map and local listings a search engine returns for it. Google says it uses a searcher's location to show nearby results even when a query names no place, and ranks local results mainly on relevance, distance and popularity; optimizing a business for these searches is local SEO.

First seen 2005 · Peaked 2008 · Retains 75% of peak Local SEO Local SEO →

Local search ads

Google Ads search ads that use location assets to feature a business's physical locations to people searching nearby, on Google Search, Google Maps or both, charged per click. Google shows them in Maps as map search ads, map suggest ads or promoted pins, and at the top of local results in Search, charging standard cost-per-click for location-detail, direction, call and website clicks.

Local SEO

Local search ecosystem

The full set of platforms, signals and third-party data sources — business profiles, citations, reviews, maps and ranking systems — that together determine how a business appears in local search. Google says it compiles Google Business Profile details from crawled web content, licensed third-party data and user contributions, and ranks local results mainly on relevance, distance and popularity, so visibility depends on more than one data source at once.

Local SEO Local SEO →

Local search intent

A searcher's aim of finding something near a particular place, whether the query names that place or leaves the search engine to infer it from the searcher's location. Google's Search Quality Rater Guidelines call a place named in a query its "explicit location" and a search for nearby places a "Visit-in-Person" query, and Google says it uses a searcher's location to show nearby results even when a query names no place.

Local SEO

Local search visibility

The extent to which a business appears in local search results: its Google Business Profile in the local pack and Google Maps, and its website in organic results. Google says it can show a business for searches such as "salons near me" when its profile information matches, and ranks local results mainly on relevance, distance and popularity; practitioners measure visibility with local rank tracking.

Local SEO

Local SEO Current · 99%

The practice of optimizing a business's Google Business Profile, website and citations so it appears in local search results for the area it serves. Google says it ranks local results mainly on relevance, distance and popularity and compiles profile details partly from crawled web content and licensed third-party data, which is why practitioners work on the profile, location pages and citations.

First seen 2017 · Peaked 2020 · Retains 99% of peak Local SEO Local SEO →

Local Services Ads

A Google Ads format that bills a business only when a customer gets in touch, showing its profile — services, hours, reviews, a Google Verified badge — prominently in Search. Businesses submit their hours, service area and services offered to generate the profile the ad shows, and Google's screening process awards the Google Verified badge to most categories, though not currently to dining businesses.

Local SEO

Location-based service In use · 64%

A digital service that uses a device's real-time geographic position to tailor the information, content or functionality it provides to the user. Browsers and apps typically obtain that position through a mechanism such as the Geolocation API, which asks the user's permission before reporting location to a site, only in a secure HTTPS context.

First seen 2004 · Peaked 2011 · Retains 64% of peak Local SEO

Log file In use · 71%

A file a web server writes, appending one entry for every request it receives, recording the requested URL, the client’s IP address and the server’s response. RFC 9110 notes that most servers add an entry to an access log as each response completes. Practitioners read those entries to see which URLs a crawler such as Googlebot requested and how the server answered; Google notes a site’s own request logs can differ slightly from Search Console’s Crawl Stats report.

First seen 2004 · Peaked 2005 · Retains 71% of peak Technical SEO

Log file analysis In use · 77%

The practice of examining a web server’s raw request log to see which URLs search engine crawlers requested, when, and how the server responded. Google recommends verifying a request with a reverse DNS lookup or its published IP ranges, since the Googlebot user-agent string is often spoofed; practitioners use the same entries to check how often and how deeply crawlers such as Googlebot reach a site’s pages.

First seen 2010 · Peaked 2015 · Retains 77% of peak Technical SEO

Long-tail keyword Fading · 31%

A longer, more specific keyword phrase that draws fewer searches on its own than a short, broad term. Wired's Chris Anderson introduced "the long tail" in an October 2004 article describing how niche, low-volume items collectively outsell a market's few hits; SEO practitioners apply the same shape to search demand, where many specific phrases can add up to more traffic than one broad term.

First seen 2005 · Peaked 2009 · Retains 31% of peak Keyword research and intent

LSI keywords

A set of words an SEO tool suggests as related to a target keyword, on the claim that adding them signals topical relevance as latent semantic indexing measures it. Latent semantic indexing itself comes from a 1990 research paper and a 1989 patent by Deerwester, Dumais, Furnas, Landauer and colleagues, describing a statistical retrieval technique, not a content-writing practice; Search Engine Roundtable reported in September 2023 that Google’s John Mueller said such keywords “have no effect,” so the SEO technique remains disputed, not confirmed.

Keyword research and intent

M

Machine learning Current · 91%

A branch of artificial intelligence in which a system improves at a task by learning patterns from data, rather than following rules a programmer wrote explicitly. Google Cloud describes machine learning as training algorithms on data so a model can predict a correct response — spotting a pattern or sorting an object into the right category, for instance — and names deep learning as one subset of it.

First seen 2005 · Peaked 2025 · Retains 91% of peak AI search and GEO

Manual action

A demotion or removal from Google’s search results that a human reviewer applies to a site after confirming its pages don’t comply with Google’s spam policies. Google’s automated systems catch most spam on their own; Search Console’s Manual actions report names the affected pages and the policy involved, and notifies the site owner by message and in the report itself.

Spam and black hat

Map spam

A fake or fraudulent Google Business Profile — for a business that doesn't exist or isn't at the stated address — built to rank in local results. Google lets anyone report a listing as offensive, harmful or misleading if they believe it may not exist, and separately prohibits reviews posted, changed or removed in exchange for payment or discounts.

Local SEO

Markdown version of a page (.md)

A plain-Markdown copy of a web page that the llms.txt proposal asks sites to publish for AI agents, at the page’s URL with .md appended or replacing its extension. The proposal says this lets agents read clean content without parsing an HTML page’s navigation and scripts, and its August 2026 revision adds two link relations for finding the copies: rel="alternate" type="text/markdown" links a page to its Markdown version, and rel="describedby" to the llms.txt file covering it.

AI search and GEO

MCP client

An AI application that connects to a Model Context Protocol server to reach the data sources, tools or workflows the server exposes. Anthropic’s announcement of the protocol describes this split directly: a developer either makes data available through an MCP server, or builds the AI application — the MCP client — that reaches out to it; MCP’s own documentation names Claude and ChatGPT as applications that support it.

AI search and GEO

MCP server

A program that exposes an application’s data, tools or workflows to AI applications over the Model Context Protocol. Anthropic’s launch of the protocol shipped pre-built servers for systems such as Google Drive, Slack, GitHub and Postgres, and MCP’s own documentation compares the protocol as a whole to a USB-C port that gives AI applications a standardized way to connect to such external systems.

AI search and GEO

Media queries

A CSS mechanism that tests values or features of the display or user agent, such as its width, so a stylesheet can apply rules only when they match. The W3C’s Media Queries spec says they’re used in CSS’s @media rule to conditionally style a document, and in other contexts such as HTML and JavaScript. MDN Web Docs says they test a device’s characteristics, such as viewport width or orientation, so a stylesheet can adapt; Google says a page’s viewport meta tag tells it the page is mobile-friendly.

Technical SEO

Metadata

A content category the HTML Standard defines for markup, such as <title>, <meta> and <link>, that “sets up the presentation or behavior of the rest of the content.” Google says the head element is the primary place for specifying metadata about a page, and that using valid HTML there ensures Google can use the metadata as documented, covering elements such as the title and meta description tags.

On-page and content

Meta description

A <meta name="description"> tag, which the HTML Standard defines as a free-form description of a page, suitable for a directory of pages such as a search engine. Google sometimes uses the tag to build a result’s snippet; a 2007 Google blog post said accurate descriptions “can improve clickthrough” but don’t affect ranking, and that ones made of long strings of keywords are less likely to be shown.

On-page and content

Meta keywords Obsolete · 5%

A <meta name="keywords"> tag, which the HTML Standard defines as a list of keywords relevant to a page and which Google’s web search ignores for ranking. The HTML Standard notes that many search engines ignore such keywords because the feature was used to spam results; Google’s documentation lists the tag as unsupported, and a 2009 Google post traced that to years of keyword stuffing.

First seen 2006 · Peaked 2006 · Retains 5% of peak On-page and content History of SEO terms on Wikipedia →

Meta refresh

An HTML tag, <meta http-equiv="refresh">, that sends the browser to a new URL, or reloads the same one, after a set number of seconds. The HTML Standard defines the refresh pragma as a timed redirect. Google recommends a server-side 301 redirect over the tag, which not all browsers support and which can confuse users, and treats an instant (0-second) meta refresh as a permanent redirect and a delayed one as a temporary redirect.

Technical SEO

Metasearch engine Fading · 50%

A search tool that sends a query to several other search engines at once and combines their results into one list, instead of crawling and indexing the web itself. MDN Web Docs describes a standard search engine’s own process in three steps: crawling the web, indexing what it finds by associating keywords with the pages that contain them, and then searching that index to find and rank pages that match a query.

First seen 2004 · Peaked 2006 · Retains 50% of peak Search fundamentals

Meta tags Obsolete · 19%

HTML <meta> elements, which the HTML Standard defines as carrying page metadata that elements such as <title> and <link> can’t express, like a page description. Google’s Search Central documentation lists which of these tags it supports, such as description and robots, and says it ignores ones it doesn’t, including the keywords tag; support for a given tag can change over time.

First seen 2004 · Peaked 2004 · Retains 19% of peak On-page and content

Mirror site

An exact copy of a website or its files, hosted at a different URL or server, often to spread load, add redundancy, or serve a different region. Because a mirror duplicates a page’s primary content exactly, Google’s canonicalization process clusters it with the original and chooses one representative URL as canonical; the mirror still gets crawled, just less often, and Google’s search result normally points to the canonical version instead.

Technical SEO

Mobile-first design

A web-design approach that starts by designing and building for small mobile screens, then progressively adds features and layout for larger screens. MDN calls the approach “a form of progressive enhancement” that contrasts with the older practice of designing for desktop screens first and only later adding limited support for smaller ones; the rationale is to secure a good experience on small screens first, then enrich it as screen size grows.

Web fundamentals

Mobile-first indexing In use · 80%

A Google Search practice of crawling, indexing and ranking a site mainly from the mobile version of its pages rather than the desktop version. Google announced on October 31, 2023, that its move to mobile-first indexing, begun in 2016, was complete, though Google still uses its legacy desktop crawler for a very small set of sites that don’t work on mobile devices. Google indexes the mobile version of most sites, so most Googlebot requests use the smartphone crawler.

First seen 2016 · Peaked 2025 · Retains 80% of peak Technical SEO

Model Context Protocol

An open standard, introduced by Anthropic, that lets AI applications connect to external data sources, tools and workflows through a common client-server interface. Anthropic open-sourced the protocol on November 25, 2024; MCP’s documentation likens it to “a USB-C port for AI applications” and says AI assistants such as Claude and ChatGPT, and tools such as Visual Studio Code and Cursor, support it.

AI search and GEO

Multi-location SEO

Local search optimization for a business that operates from more than one location, giving each its own Google Business Profile and keeping all of them consistent. Google Business Profile guidelines allow no more than one profile per location and require a chain's locations to share the same name and category; once a business has 10 or more locations, Google lets it verify and manage them in bulk.

Local SEO

Multimodal search

Search that accepts more than one input type at once, such as an image combined with typed text, to return results relevant to all of them together. Google’s Machine Learning Glossary defines a modality as a high-level data category such as text or images, and Google documents two ways to combine an image with typed text in one query: uploading or dragging an image into Search, or circling it on-screen with Circle to Search.

AI search and GEO

Multivariate testing Fading · 48%

A method of testing more than one element of a page at once, to see the effect of each change and how changes interact. Google Search Central’s guidance for A/B tests, such as using rel=“canonical” on variant URLs and 302 rather than 301 redirects, applies equally to multivariate tests because both create alternate URLs or on-page variations that Googlebot can crawl.

First seen 2007 · Peaked 2011 · Retains 48% of peak Analytics and rank tracking

MUM Multitask Unified Model

An AI model, introduced by Google in May 2021, capable of both understanding and generating language across 75 languages and multiple content formats. Google says MUM is roughly a thousand times more powerful than BERT, but unlike BERT and RankBrain it is not currently used for general Search ranking, instead powering specific features such as COVID-19 vaccine information and featured-snippet callouts.

Algorithms and updates

N

NAP name, address and phone number

The name, address and phone number of a business, the three details that identify a business location in local listings and directories. Google Business Profile guidelines set a rule for each part: the name used in the real world, a precise address or service area, and a phone number that reaches the individual location. Google also says it compiles profile details from sources including crawled web content and licensed third-party data.

Local SEO Local SEO →

NAP consistency

The degree to which a business's name, address and phone number match everywhere they appear online, from its own website to directories and other citations. Google says it compiles Google Business Profile details partly from crawled web content and licensed third-party data, and its guidelines require a chain's locations to share the same name and category, though its local ranking guidance never names consistency as a ranking factor.

Local SEO Local SEO →

Natural language generation In use · 86%

The subfield of natural language processing concerned with producing fluent human-readable text, such as a summary or an answer, from data or a model rather than analyzing existing text. Microsoft’s Azure architecture guidance describes NLP broadly as analyzing, understanding and generating language, and its language-models comparison table narrows that: language models are the deep-learning subset focused on high-level understanding and generation tasks, producing fluent text such as summaries and answers rather than the labels and scores plain NLP techniques return.

First seen 2004 · Peaked 2010 · Retains 86% of peak AI search and GEO

Natural language processing In use · 83%

The field of computer science that teaches computers to analyze, interpret or produce what a person said or typed in ordinary human language. Google’s Machine Learning Glossary says nearly every present-day NLP system now depends on machine learning rather than hand-written linguistic rules alone, and treats natural language understanding, which determines intent, context and sentiment, as one subset of the broader field.

First seen 2004 · Peaked 2011 · Retains 83% of peak AI search and GEO

Natural language understanding Fading · 41%

A subfield of natural language processing focused on determining what a person means by what they typed or said, including context, sentiment and other cues plain parsing misses. Google names two of its ranking systems, BERT and RankBrain, as AI systems built to interpret word meaning and intent rather than match on exact keywords, and says its generative AI features are “rooted in” those same core Search ranking and quality systems.

First seen 2004 · Peaked 2004 · Retains 41% of peak AI search and GEO

Near-me query

A search that asks for something close to the searcher, such as "salons near me," without naming a specific place. Google always estimates the general area a search comes from, and uses a device's precise location instead when the user has granted permission, resolving the query without an explicit place name.

Local SEO

Negative SEO In use · 88%

Actions a third party takes against someone else’s site, such as building spammy backlinks to it, intended to damage its search rankings rather than improve the attacker’s own. Google’s Search Console Help says it “works hard to prevent other site owners from being able to harm your ranking or have your site removed from” its index, and points to the disavow tool for links a site cannot otherwise get removed.

First seen 2015 · Peaked 2020 · Retains 88% of peak Spam and black hat

Neural network Current · 94%

A machine-learning model built from layers of connected nodes, called neurons, that each weigh their inputs and pass a signal to the next layer. Google’s Machine Learning Glossary defines the type as any model with at least one hidden layer and calls the computer-implemented version an artificial neural network, to distinguish it from the networks of neurons in a brain.

First seen 2004 · Peaked 2025 · Retains 94% of peak AI search and GEO

nofollow Fading · 35%

A link attribute, rel="nofollow", that the HTML Standard defines as marking a link its page’s author or publisher does not endorse, or one included mainly for a commercial relationship. Google announced it on January 18, 2005, with MSN Search and Yahoo! backing it, to fight comment spam; since September 2019 Google has treated nofollow, like rel="sponsored" and rel="ugc", as a hint rather than a directive, for crawling and indexing too from March 1, 2020. A nofollow robots rule covers every link on a page.

First seen 2005 · Peaked 2010 · Retains 35% of peak Links and authority Free SEO Chrome extension →

noindex

A rule, set in a robots meta tag or an X-Robots-Tag HTTP header, that asks search engines supporting it to keep a page or file out of their index. Google drops a page from its results once it crawls the page and finds the rule, even if other sites link to it. If robots.txt blocks the page, Google never sees the rule and the URL can still appear in results, and Google does not support noindex inside robots.txt.

Technical SEO Technical SEO audit →

Non-commodity content

Google’s term for content offering a unique expert or first-hand take, contrasted with commodity content — generic material based on common knowledge that any writer could have produced. Google’s guide says content like this shapes AI-search visibility more than anything else it recommends, contrasting “7 Tips for First-Time Homebuyers” as its example of commodity content with a personal account of skipping a home inspection as the non-commodity alternative.

AI search and GEO

(not provided)

A placeholder Google Analytics shows for an organic search query it can’t read, because most Google searches now run over HTTPS. Google’s own Analytics documentation says HTTPS search causes the keyword dimension to be set this way automatically; Google had announced the shift toward encrypted, signed-in search in an October 18, 2011 blog post, after which sites could see that a visit came from Google but not the query that led to it.

Analytics and rank tracking

O

OAI-SearchBot

The web crawler OpenAI uses to surface websites in ChatGPT search, separate from GPTBot, the crawler that gathers content for training OpenAI’s models. OpenAI says a site that disallows OAI-SearchBot in robots.txt won’t appear in ChatGPT search answers, though it can still show as a navigational link, and that a robots.txt update can take about 24 hours to take effect.

AI search and GEO

Off-listing signals

Local ranking inputs that come from outside a Google Business Profile itself, such as backlinks and reviews elsewhere on the web, rather than fields the owner edits on the listing. Google says prominence is "also based on info like how many websites link to your business and how many reviews you have," factors it compiles partly from crawled web content and licensed third-party data rather than owner edits.

Local SEO

Off-page SEO

SEO work that happens away from a site’s own pages, chiefly earning backlinks and mentions elsewhere. Google says its link-analysis systems, including PageRank, use how pages link to each other to work out what each page covers and which might help most, and that it primarily finds pages through links from pages it has already crawled.

Links and authority

One-pager

A website built as a single HTML page, with sections a visitor reaches by scrolling or clicking in-page anchor links instead of navigating to separate URLs. Because Google Search generally doesn’t treat a URL fragment, the part after a #, as a different page, a one-pager’s sections aren’t separate crawlable or indexable URLs the way pages on a multi-page site are; all of its content and links compete under one title, one meta description and one URL.

Technical SEO

Online reviews

Public first-party or third-party feedback that customers post about a business online, typically a star rating with written text. Google's Search Quality Rater Guidelines treat many detailed, trustworthy, positive reviews as evidence of a business's positive reputation, but instruct raters to weigh what a review says over its star count, since anyone — including a business itself — can write one.

Local SEO

On-page SEO

The practice of adjusting elements a page owner controls directly — titles, headings, body text, URLs and internal links — to help a page rank and earn clicks. Google’s SEO Starter Guide groups its advice on how a page appears in Search around choices such as the title link, snippet and images, while a 2009 Google post set on-page content apart from “off-page” factors such as inbound links.

On-page and content

Open Graph Fading · 49%

A protocol, published at ogp.me, that lets a page describe itself with og: meta tags so social platforms can render it as a rich object when shared. The protocol was originally created at Facebook, and ogp.me publishes its specification under the Open Web Foundation Agreement; Google’s documentation lists an og:title meta tag as one source it may use to generate a page’s title link, and its Images guidance accepts an og:image tag as an alternative to schema.org markup for choosing a page’s preferred image.

First seen 2012 · Peaked 2016 · Retains 49% of peak On-page and content Free SEO Chrome extension →

Optional section (llms.txt)

The H2 section headed “Optional” in an llms.txt file, used by convention for secondary links that an AI agent can skip when it needs a shorter context. Version 2 of the llms.txt proposal, from August 2026, keeps the section only as a convention: it dropped the context-expansion tooling that gave “Optional” a special meaning, telling those tools which links to leave out.

AI search and GEO

Opt-out header

A Content-Usage HTTP header, proposed in an IETF Internet-Draft, letting a server state whether a system may use its content for AI training, general AI use, or search. The IETF’s AI Preferences working group proposes the header, in a draft co-authored by Google’s Gary Illyes and Mozilla’s Martin Thomson, alongside a matching robots.txt rule; as of September 2026 both remain Internet-Drafts still under working-group discussion, not yet published as an RFC.

AI search and GEO

Organic search Fading · 46%

Unpaid search as a whole: the results a search engine ranks without payment and the visits they send to sites, as opposed to paid search. Google says it takes no money to include or rank sites in its results and that appearing in its organic results costs nothing; Google Analytics counts the visits they send as its Organic Search channel, separate from Paid Search.

First seen 2005 · Peaked 2005 · Retains 46% of peak Search fundamentals

Organic search results Current · 91%

The free listings on a search results page that appear because they’re relevant to the query, as distinct from paid ads. Google Ads’ own glossary defines an organic search result as “a free listing in Google Search that appears because it’s relevant to someone’s search terms,” contrasted with ads, which carry a “Sponsored” box; Search Console’s Performance report counts clicks and impressions for these unpaid results.

First seen 2005 · Peaked 2022 · Retains 91% of peak Search fundamentals Rank tracking →

Orphan page

A page on a site with no internal links pointing to it, so a crawler following links from other pages can’t reach it. Google says “every page you care about should have a link from at least one other page on your site,” and that on large sites it’s harder to ensure this, so Googlebot may miss some new pages. A sitemap or an external link can still lead Google to an orphan page.

Technical SEO

P

Page experience

Google’s framing for how good a page is to visit, covering Core Web Vitals, mobile-friendly display, a secure HTTPS connection, and freedom from intrusive interstitials. Google says there is no single page-experience ranking signal and that its ranking systems use Core Web Vitals; the other aspects don’t directly raise rankings but can make a site more satisfying to use, which aligns with what those systems seek to reward.

Page experience

Page experience update

A Google Search ranking change, announced in May 2020, that folded Core Web Vitals and existing usability signals into a single page-experience signal. Google rolled the signal into mobile ranking gradually between June and August 2021, then announced in November 2021 that desktop ranking would use it starting February 2022, with rollout complete by the end of March 2022.

Algorithms and updates

Page rank Obsolete · 10%

The two-word spelling of PageRank, Google’s link-based scoring algorithm, as written in lowercase in Larry Page’s original patent for the method. The patent, filed in 1998, uses the phrase for the score its method assigns — “this definition yields a page rank that increases as the number of backlinks increases” — while Google writes PageRank as one word and says it remains part of its core ranking systems.

First seen 2004 · Peaked 2004 · Retains 10% of peak Search fundamentals

PageRank Fading · 46%

One of Google’s core ranking systems, named for co-founder Larry Page, that scores a page by treating each link to it as a vote weighted by the linking page’s standing. Google’s guide says PageRank was one of its core ranking systems at launch and remains part of them today, though how it works has evolved considerably since the 1998 paper and patent that first described it.

First seen 2004 · Peaked 2006 · Retains 46% of peak Algorithms and updates

Page speed In use · 82%

The rate at which a page’s content loads and becomes usable for a visitor, commonly measured through metrics such as Largest Contentful Paint and Time to First Byte. Largest Contentful Paint, a Core Web Vitals metric, scores one aspect of loading speed, and Google says its ranking systems use Core Web Vitals; other common page-speed metrics, such as Time to First Byte, are not Core Web Vitals themselves.

First seen 2017 · Peaked 2023 · Retains 82% of peak Page experience

Pageview Fading · 55%

A single load of one page in a browser, the basic unit web analytics platforms use to count how much a site’s pages are viewed. Google Analytics 4 logs a pageview as an automatically collected page_view event, fired each time a page loads or the browser’s history state changes on a site with enhanced measurement turned on.

First seen 2005 · Peaked 2009 · Retains 55% of peak Analytics and rank tracking

Panda

A Google ranking system, announced in February 2011, that aimed to rank high-quality, original content above low-value and copied pages. Google’s launch post said the change noticeably affected 11.8% of its queries and was designed to lower rankings for sites that copied content or added little value while raising sites with original research and analysis.

Algorithms and updates

Parametric knowledge

The facts and associations an AI model has encoded in its own trained weights, as opposed to information it looks up from an external source when it answers. The paper that introduced retrieval-augmented generation pairs this parametric memory with a non-parametric, searchable index, noting that updating a model’s world knowledge and providing provenance for its decisions remain “open research problems.”

AI search and GEO

Passage ranking system

An AI system that identifies individual passages within a web page to judge how relevant that specific section is to a search, separate from the page’s overall relevance. Google introduced the capability in an October 2020 blog post, saying it would improve 7% of search queries globally as it rolled out; Google’s ranking systems guide now lists it among current ranking systems.

Algorithms and updates

Pay-per-click Fading · 50%

An advertising pricing model, most often used in paid search, in which an advertiser pays only when someone clicks its ad. Google Ads documentation says cost-per-click pricing “is sometimes known as pay-per-click (PPC)”; under it, an advertiser sets a maximum bid per click, and an auction that runs with every search decides whether and where the ad appears.

First seen 2004 · Peaked 2006 · Retains 50% of peak Search fundamentals

PDF Portable Document Format

A file format, standardized by ISO as ISO 32000, for exchanging and viewing an electronic document independent of the environment in which it was created, viewed or printed. Google Search lists Adobe Portable Document Format (.pdf) among the encoded file types it indexes, using a specific parser to extract the file’s human-readable text so that content can be indexed.

Web fundamentals

Penalty

Practitioner shorthand for a drop in a site’s Google rankings or visibility, whether from a manual action or from an algorithmic ranking change. Google’s own spam-policy and Search Console documentation almost always uses “manual action,” not “penalty”; its site reputation policy FAQ uses “manual penalty” just once, for a lifted manual action. Google’s own core-update posts name “manual or algorithmic action” as the two things that can happen to a page found in violation, and practitioners’ “penalty” spans both.

Spam and black hat

Pending (listing status)

A Google Business Profile edit status that Google shows while a submitted change is still being reviewed, before it's marked either accepted or not approved. Google says a pending edit is usually reviewed within about 10 minutes but can take up to 30 days, and Pending is one of exactly three outcomes it names, alongside Accepted and Not approved.

Local SEO

Penguin In use · 83%

A Google ranking system, announced in April 2012, designed to combat link spam by lowering rankings for sites Google judged to be manipulating links. Google’s launch post said the change affected about 3.1% of English queries to a noticeable degree, and a 2016 update made Penguin real-time and more granular, devaluing spam signals for specific pages rather than whole sites.

First seen 2012 · Peaked 2017 · Retains 83% of peak Algorithms and updates

People Also Ask

A group of related questions in Google Search results that expand to show a featured-snippet-style answer, which Google’s own documentation calls a “related questions group.” When a user expands one of the questions, Google shows a featured snippet as the answer, so the guidance for managing featured snippets also governs what can appear here.

SERP features

Perplexity Current · 100%

An AI-powered answer engine and search company that generates cited, conversational answers to queries instead of a ranked list of links. Perplexity’s documentation calls the search behind its product “Perplexity’s own answer engine,” and the company runs separate agents for it: PerplexityBot for search results and Perplexity-User for live user requests.

First seen 2023 · Peaked 2026 · Retains 100% of peak AI search and GEO

PerplexityBot

The web crawler Perplexity uses to surface and link websites in its search results, separate from Perplexity-User, which fetches pages when a person asks a question. Perplexity says PerplexityBot “is not used to crawl content for AI foundation models” and recommends allowing it in robots.txt, along with its published IP ranges, so a site can appear in Perplexity’s search results; changes can take up to 24 hours to apply.

AI search and GEO

Perplexity-User

The user agent Perplexity uses to visit a web page when a person asks Perplexity a question, so the answer can draw on and link to that page. Perplexity says this fetcher is not used for web crawling or to collect training data and, because a person triggered the request, it generally ignores robots.txt rules, unlike the separate PerplexityBot crawler.

AI search and GEO

Personalized search In use · 74%

Search results reordered or adjusted for an individual searcher based on signals such as account activity, location or past searches, rather than shown identically to everyone. Google says personalization “is only used if it can provide information that’s likely to be more helpful,” changes the order of some results rather than all of them, and can be turned off; even then, Google still uses signals such as location, language and device type.

First seen 2004 · Peaked 2013 · Retains 74% of peak Search fundamentals

Phone number (listing) In use · 70%

The telephone number listed for a business on its Google Business Profile and other local listings, one of the three core NAP details. Google requires a number that connects directly to the individual location and stays under the business's control, prefers a local number over a central helpline, and bars premium-rate numbers whatever the caller would be charged.

First seen 2004 · Peaked 2015 · Retains 70% of peak Local SEO

Physical address

The real-world street address of a business location, as distinct from a mailbox, virtual office or other address the business doesn't operate from. Google requires a precise, accurate address for a business's actual, real-world location, rejects P.O. boxes and remote mailboxes outright, and excludes a rented address the business doesn't operate from, which it calls a virtual office.

Local SEO

Pigeon

A change to Google’s local search algorithm, launched in the US on July 24, 2014, that ties local ranking more closely to Google’s web search signals. Search Engine Land named the update Pigeon in its July 24, 2014 report; Google itself has never used that name, though it confirmed the algorithm improves distance and location ranking and draws on web-ranking signals such as spelling correction and synonyms.

Algorithms and updates

Pillar page

A page that gives a broad, comprehensive overview of a topic and links out to narrower pages, called cluster pages, that each cover one of its subtopics in depth. Google’s SEO Starter Guide says grouping topically similar pages and linking between them helps both Google and users understand how a site’s pages relate — the structural logic the pillar-and-cluster pattern is built on.

On-page and content

Pillars of local search

An industry name for the three factors Google says it mainly ranks local results on: relevance, distance and popularity. Google's local ranking page explains each under its own heading: Relevance, how well a profile matches the search; Distance, how far the business is from the searcher; and Prominence, how well-known it is. The page never calls the set "pillars."

Local SEO

Place label

A personal, custom name that a Google Maps user attaches to a place they save for their own reference. Google calls this a private label: labeled places show up on that user's own map, in their search suggestions and in Google Photos.

Local SEO

Place topics

Short, recurring themes that Google Business Profile surfaces from the keywords and phrases customers repeat across a business's reviews. Google generates Place Topics automatically once a business has enough quality reviews, can't create them on demand, and lets searchers click a topic to filter straight to the reviews that mention it.

Local SEO

Plugin Current · 91%

A software add-on, installed into a platform such as a content management system or browser, that adds a feature without altering the platform’s core code. WordPress’s own developer docs call its plugins “packages of code that extend the core functionality of WordPress,” built from PHP plus assets such as images, CSS and JavaScript; the same word names comparable add-ons in other platforms, such as browsers and design tools.

First seen 2004 · Peaked 2012 · Retains 91% of peak Web fundamentals

PO Box

A mailbox rented at a post office rather than a real-world street address, which Google Business Profile guidelines exclude from local listings. Google's guidelines say P.O. boxes or mailboxes at remote locations aren't acceptable, and require a business to create its profile for its actual, real-world location instead.

Local SEO

Pogo-sticking

An industry name for a searcher clicking a result, then quickly returning to the results page to click another, read as a sign of a poor match. Google’s Andrey Lipattsev said in 2016 that pogo-sticking “isn’t always a good metric” and that the company’s own statistical tests found it “don’t make for better quality” as a ranking signal.

Analytics and rank tracking

Pop-up Fading · 31%

A window or in-page overlay that appears on top of a page’s main content without the visitor directly asking for it. Pop-ups opened as a separate browser window rely on JavaScript’s window.open, which modern browsers block unless a user directly triggers it; Google calls a whole-page overlay an interstitial and a partial one a dialog, and says intrusive ones can make content hard for search engines to understand.

First seen 2004 · Peaked 2004 · Retains 31% of peak Page experience

Preload

A resource hint, written as <link rel="preload">, that tells the browser to fetch a specific resource early, before it would normally be discovered, because the page will need it soon. The as attribute tells the browser what kind of resource to expect, while the fetchpriority attribute sets its request priority; WHATWG’s HTML Standard says a preloaded resource is fetched because the user is highly likely to need it for the current navigation, and a user agent must not delay the page’s load event for it.

Page experience

Private blog network Current · 95%

A group of websites, often built on purchased expired domains, that one operator secretly controls in order to link to a separate site and inflate its rankings. Google’s own documentation never uses this name; it addresses the underlying tactic through its link spam policy, which bans using “automated programs or services to create links,” and its expired domain abuse policy, which bans repurposing an expired domain “primarily to manipulate search rankings.”

First seen 2015 · Peaked 2023 · Retains 95% of peak Spam and black hat

Product page SEO Fading · 54%

The on-page and technical work applied to a product page — content, structured data and URL design — to help it rank and display well in Search. Google Search can show a product’s price, availability and review ratings straight in results when the page carries Product structured data, either on its own or combined with a Merchant Center feed.

First seen 2005 · Peaked 2017 · Retains 54% of peak E-commerce and international

Product/service keywords

The words and phrases naming what a business sells or does, which searchers use in queries and which a Google Business Profile's category and content are meant to match. Google says the category a business selects affects its local ranking and can put it in results for related searches — a profile with the primary category "Pizza restaurant" can surface for a search for "Italian restaurants."

Local SEO

Prominence

One of the three factors Google says its local results are mainly based on, defined by Google as how well-known a business is. Google's local ranking page calls this factor "popularity" in its summary and "Prominence" in the section that explains it, which bases it partly on how many websites link to a business and how many reviews it has; Google says more reviews and positive ratings can help local ranking.

Local SEO Local SEO →

Prompt

The text a person or application sends to an AI model to elicit a specific response, distinct from any system-level instructions layered on top of it. OpenAI’s API documentation gives instructions passed through a separate parameter priority over a prompt supplied as input, and Anthropic and OpenAI both publish prompt-engineering guides describing techniques for wording a prompt to get a consistent result.

AI search and GEO

Prompt engineering Current · 100%

The practice of writing and revising the instructions given to an AI model so it reliably produces the kind of response a person wants. OpenAI defines it as writing instructions precise enough that a model “consistently generates content that meets your requirements,” and both OpenAI and Anthropic publish extensive guides of techniques, such as giving examples or assigning the model a role, for doing it well.

First seen 2021 · Peaked 2026 · Retains 100% of peak AI search and GEO

Prompt injection Current · 100%

A security exploit in which crafted text makes an AI system follow an attacker’s hidden instructions instead of its developer’s or user’s. Simon Willison named the exploit in September 2022, after Riley Goodside demonstrated it against GPT-3. OWASP’s LLM Top 10 separates direct injection from indirect injection, where instructions are hidden in “external sources” such as a web page; Anthropic warns “every webpage an agent visits is a potential vector for attack,” and Bing’s guidelines ban content meant to manipulate the models behind Bing and Copilot.

First seen 2022 · Peaked 2026 · Retains 100% of peak Spam and black hat

Proximity

An industry name for how close a business is to the searcher, one of the three factors Google says its local results are mainly based on. Google's own ranking guidance names this factor Distance, not proximity, and says it depends on how far each candidate business is from a searcher who shares their location or whose location Google estimates.

Local SEO

Q

Quality link

Practitioner shorthand for a backlink from a relevant, trustworthy site likely to carry real ranking value. The idea draws on PageRank, in which a link from a highly ranked page counts for more, and Google says PageRank remains part of its core ranking systems; Google also says external links can “help establish trustworthiness.”

Links and authority

Quality Score Fading · 50%

A Google Ads diagnostic score, from 1 to 10, estimating how relevant and useful an advertiser’s ad and landing page are for a keyword, compared with other advertisers. Google calculates it from three components — expected clickthrough rate, ad relevance and landing page experience — and says Quality Score “is not an input in the ad auction” but a diagnostic tool, distinct from Ad Rank, which does help decide where an ad appears.

First seen 2006 · Peaked 2009 · Retains 50% of peak Search fundamentals

Query deserves freshness

Google’s name for systems that show fresher content for queries where recent information is expected, such as breaking news or a newly released movie. The phrase surfaced publicly in a 2007 New York Times profile of Google engineer Amit Singhal’s team, which described a model called QDF that judged whether a topic was “hot” from news coverage and Google’s own query stream.

Algorithms and updates

Query fan-out

Google’s technique of issuing several related searches behind the scenes to gather more source material before composing a single AI-generated response. Google names query fan-out as a technique behind both AI Overviews and AI Mode; a single question about fixing a weedy lawn, for example, can trigger related searches for herbicides and weed prevention, surfacing a wider set of supporting links than a classic search.

AI search and GEO AI search optimization →

R

RankBrain In use · 78%

An AI system, launched in 2015 as Google’s first deep-learning ranking system, that helps Google Search relate the words in a query to broader concepts. Google says RankBrain helps return relevant results even when a query doesn’t contain a page’s exact words, by matching the query’s underlying concept; Google’s ranking systems guide still lists it among current systems.

First seen 2015 · Peaked 2018 · Retains 78% of peak Algorithms and updates

Reciprocal links Fading · 35%

Links between two sites that each agree to link back to the other, whether that exchange happens naturally or is arranged to manipulate rankings. Google’s link spam policy names two examples: “excessive link exchanges” and automated cross-linking schemes done to manipulate rankings; it does not address an occasional reciprocal link between genuinely related sites.

First seen 2005 · Peaked 2007 · Retains 35% of peak Spam and black hat History of SEO terms on Wikipedia →

Recrawl

A request, or a routine revisit, that gets a search engine’s crawler to fetch a URL again to pick up changes since the last crawl. Google’s URL Inspection tool lets a Search Console owner or full user request a crawl of individual URLs, and a submitted sitemap helps Google discover many URLs at once; Google says requesting a crawl doesn’t guarantee that inclusion in search results happens instantly, or at all, and that resubmitting the same URL repeatedly won’t make it crawl any faster.

Technical SEO

Redirect In use · 76%

An instruction that sends a browser or crawler requesting one URL to a different URL instead, so visitors and search engines land on the page’s current address. RFC 9110 groups HTTP redirects under the 3xx status codes. Google treats a permanent redirect, such as a 301, as a strong signal that the target should become canonical, and a temporary one, such as a 302, as only a weak signal, keeping the original URL in search results.

First seen 2004 · Peaked 2006 · Retains 76% of peak Technical SEO

Redirect chain

A sequence of two or more redirects that a browser or crawler must follow, one after another, before reaching a URL that returns content instead of another redirect. Google’s crawlers follow at most 10 redirect hops by default before giving up, and Google’s inspection tools, such as the URL Inspection tool, don’t follow redirects at all, so a long chain can keep a page from being crawled, indexed or tested.

Technical SEO Technical SEO audit →

Redirect loop

A chain of redirects that leads back to a URL already visited, so the sequence never reaches a page that actually loads. MDN Web Docs says a server that detects the loop typically returns a 500 Internal Server Error; when the loop spans multiple servers that can’t detect it, browsers such as Chrome and Firefox show their own redirect-loop error instead of a page.

Technical SEO

Referral traffic In use · 76%

Visits that arrive at a site by clicking a link on another site or app, other than a paid ad or a search result. Google Analytics 4 assigns the Referral channel to non-ad links from other sites and apps, such as blogs or news sites, distinguishing it from Organic Search and paid channels in the traffic acquisition report.

First seen 2012 · Peaked 2024 · Retains 76% of peak Analytics and rank tracking

Referring domain

The unique root domain a backlink comes from, counted once no matter how many individual links or pages on it point to a site. Google’s Search Console groups external links the same way in its Links report, showing linking “sites” by root domain with subdomains folded in, and its “Top linking sites” view sorts those root domains by count of links; that help page calls the grouping “root domain,” not “referring domain.”

Links and authority Periodic Table of SEO →

rel="alternate" type="text/markdown"

A proposed link relation that points from an HTML page to a plain-Markdown version of that same page, meant for AI agents rather than browsers. The llms.txt proposal recommends this relation, provided as an HTML link tag or an HTTP Link response header, alongside a matching rel="describedby" link; Google says Google Search doesn’t use this kind of markup and ignores it either way.

AI search and GEO

rel="describedby"

A proposed link relation that points from a page, or its Markdown alternate, to the llms.txt file describing the site section it belongs to. The llms.txt proposal recommends pairing this relation with rel="alternate" type="text/markdown", either as an HTML link tag or an HTTP Link header, so an llms.txt file at a given path covers every page under it; Google says Google Search ignores this markup.

AI search and GEO

rel="sponsored"

A link attribute that tells Google a link exists because of an ad, sponsorship or other paid arrangement. Google announced it alongside rel="ugc" on September 10, 2019; its documentation lists both among the values for qualifying outbound links, and Google treats sponsored, ugc and nofollow as “hints about which links to consider or exclude within Search.”

Links and authority Free SEO Chrome extension →

rel="ugc" user-generated content

A link attribute flagging a link as coming from user-generated content, such as a comment or forum post, rather than a site’s own editorial voice. Google announced it alongside rel="sponsored" on September 10, 2019, recommending it for links in comments and forum posts; its documentation lists it among the values for qualifying outbound links, and Google treats ugc, sponsored and nofollow as “hints about which links to consider or exclude within Search.”

Links and authority

Related searches

A cluster of related search queries, shown on a Google Search results page, that other people have also searched. Google generates the group automatically from the original query and other searches people have made; clicking one takes the user to a new results page, and Google gives site owners no way to control which searches appear.

SERP features

Relative URL

A URL that omits the scheme and domain and is resolved against the address of the page that contains it to reach a full destination. RFC 3986 defines this as a relative reference, resolved through a base URI rather than typed in full. Google’s URL structure guidance warns that a parent-relative link placed on the wrong page can generate endless bogus addresses, and recommends root-relative links instead.

Technical SEO

Relevance Current · 91%

A search engine’s measure of how closely a result matches what a searcher is looking for, and one of the key signals Google names for ranking results. Google calls a page containing the same keywords as the query “the most basic signal that information is relevant,” and says it also uses aggregated, anonymized interaction data to estimate relevance, without analyzing subjective concepts such as a page’s viewpoint.

First seen 2004 · Peaked 2004 · Retains 91% of peak Search fundamentals

Relevance (local ranking factor)

One of the three factors Google says its local results are mainly based on, defined by Google as how well a Google Business Profile matches what someone searches for. Google tells owners to provide complete, detailed business information so its systems can better match a profile to relevant searches, and says relevance works together with distance and popularity to find the best match.

Local SEO

Reputation management In use · 81%

The practice of monitoring and influencing what people find when they search for a business, from reviews and ratings to news coverage and other public mentions. Google's own quality raters are trained to weigh detailed, credible reviews over star counts alone when judging a business's reputation, and a verified business can reply publicly to reviews from its Google Business Profile.

First seen 2007 · Peaked 2015 · Retains 81% of peak Local SEO Local SEO →

Reserve with Google

A Google service that lets people search, book and pay for an appointment or reservation with a local business directly through Google Search or Maps. Google says the service works only in certain countries or regions and only through supported scheduling providers; a business without one can find a provider through Reserve with Google or add its own booking link to its Google Business Profile.

Local SEO

Responsive web design In use · 68%

A web design approach that serves identical HTML on one URL to every device, then uses CSS to adapt the page’s layout to the screen size. Google recommends responsive design over its two other mobile configurations, dynamic serving and separate URLs, calling it the easiest to implement and maintain.

First seen 2012 · Peaked 2017 · Retains 68% of peak Technical SEO

Retrieval-augmented generation Current · 100%

A technique that pairs a language model with a live search step, so it can ground its response in retrieved documents instead of relying on training data alone. Patrick Lewis and eleven co-authors introduced the technique in a 2020 paper combining a pre-trained model’s own parameters with a searchable index; Google’s guide to generative AI search says its own systems use RAG, which it also calls grounding, to pull from its Search index.

First seen 2023 · Peaked 2026 · Retains 100% of peak AI search and GEO

Returning users

In Google Analytics 4, the count of unique users active in a date range who had also started at least one earlier session before it. GA4 counts a return even if that earlier session was never an engaged session; the New users metric instead counts users logging their first first_visit or first_open event in the range.

Analytics and rank tracking

Reverse geocoding Fading · 47%

The process of converting a latitude-longitude pair, or a place ID, into a readable street address. Google's Geocoding API performs this as the inverse of ordinary geocoding, which converts an address into coordinates, and practitioners use the resulting address for tasks such as matching a delivery or pickup point to a location.

First seen 2005 · Peaked 2009 · Retains 47% of peak Local SEO

Reverse index

A data structure that maps each word to the documents containing it, letting a search engine jump to candidate pages for a query instead of scanning every document. Google’s original research paper built this structure by re-sorting its per-document “forward” index by word, calling the result the inverted index, which its searcher then used to answer queries.

Search fundamentals

Review attributes

The specific pieces of feedback inside a review — its star rating, written text, and any recurring keywords Google extracts into that business's Place Topics. Google Maps lets a reviewer add a star rating and written text, and separately mines the concise keywords and phrases customers repeat across reviews to generate a business's Place Topics.

Local SEO

Review count

The total number of reviews a business has received on a listing, one input Google uses to judge how prominent it is. Google names how many reviews a business has among the info behind prominence and says more reviews and positive ratings can help local ranking, though that guidance gives no target number or minimum.

Local SEO

Review filter

An industry name for the automated system a review platform uses to detect and withhold reviews it judges fake, spammy or otherwise policy-violating from a business's public rating. Google says it uses automated spam detection to remove reviews identified as spam, and that the system can occasionally flag a legitimate review by mistake; if Google decides not to remove a flagged review, the business that reported it can submit a one-time appeal.

Local SEO

Review gating

The practice of asking only customers who seem satisfied to post public reviews, for example by inviting reviews only after private feedback comes back positive. Google’s Maps content policy bars merchants from selectively soliciting positive reviews. The FTC’s Consumer Reviews and Testimonials Rule, in effect since October 2024, has no specific ban on gating, but FTC staff say the practice could violate the FTC Act.

Local SEO

Review management

The ongoing practice of monitoring, responding to and encouraging customer reviews across the platforms where a business is listed. Google lets a verified owner reply publicly to a review and says a helpful, positive reply can help a business stand out; its local ranking guidance also ties prominence partly to how many reviews a business has and how positive they are.

Local SEO

Review response

A business owner's public reply to a customer review, posted beneath the review on the same listing. Google checks a reply against its content policies before publishing it, usually within 10 minutes but sometimes up to 30 days, then notifies the reviewer and labels the reply as coming from the business rather than a named person.

Local SEO

Review spam

A review that breaks a platform's content policies, a wider category than fake reviews that also includes off-topic posts and reviews meant to harass a business. Google's Maps content policy bars fake engagement, including paid reviews, and removes violations, and the FTC's Consumer Reviews and Testimonials Rule, in effect since October 21, 2024, makes it illegal for a business to write or sell a review that misrepresents whether the reviewer exists or had experience with the business.

Local SEO

Reviews system

Google’s system for evaluating first-party review content, such as articles or comparison pages that recommend, compare or analyze something, rather than user-submitted product reviews. Google says it aims to reward in-depth, original analysis by experts or enthusiasts over thin content that just summarizes products, and may evaluate a whole site if reviews are a substantial part of it.

Algorithms and updates

Review station

An industry term for a physical kiosk, tablet or printed QR code a business sets up on-site to prompt customers for a review on the spot. Google's Maps content policy says a merchant soliciting reviews shouldn't require or pressure a customer to leave one while on the premises, or ask that specific content be included.

Local SEO

Review velocity

An industry term for the rate at which a business accumulates new customer reviews over a given period, such as reviews per month. Google's local ranking guidance ties prominence partly to how many reviews a business has and how positive they are, and Google says a new review can take up to two weeks to appear in a business's published score.

Local SEO

Rich result In use · 89%

A Google Search result that goes beyond a plain text listing to show graphical elements or an interactive experience, built from structured data in a page’s markup. Google adds and removes specific rich result types on its own schedule: it restricted FAQ rich results to well-known, authoritative government and health sites in September 2023, then retired the feature entirely on May 7, 2026.

First seen 2009 · Peaked 2021 · Retains 89% of peak SERP features

Robots meta tag

An HTML <meta> element, placed in a page’s head, that gives search engines page-specific instructions for indexing and serving that one page. Google reads rules such as noindex from this tag anywhere in the HTML, though a rule aimed at one crawler, like AdsBot-Google, is needed to affect non-search crawlers. For file types the tag can’t reach, such as PDFs, videos or images, the same rules go in an X-Robots-Tag HTTP header instead.

Technical SEO

robots.txt Fading · 53%

A plain-text file, defined by RFC 9309 as the Robots Exclusion Protocol, that a site publishes at its root to tell crawlers which URLs they may request. Google says the file mainly manages crawl traffic rather than hiding a page from Search: a page blocked by robots.txt can still appear in results if other sites link to it, since Google never crawls it to see a noindex rule.

First seen 2004 · Peaked 2005 · Retains 53% of peak Technical SEO

Root directory Fading · 28%

The top-level directory of a site’s file and URL structure, the base folder from which every other page or file path branches. RFC 9309 requires a robots.txt file to sit in this top-level path, such as https://www.example.com/robots.txt, to take effect for the whole site.

First seen 2004 · Peaked 2007 · Retains 28% of peak Technical SEO

RSS Really Simple Syndication Obsolete · 18%

An XML-based file format, maintained by the RSS Advisory Board, that lists a site’s recent content, such as articles, so feed readers can check for updates without visiting the site. The current specification says RSS’s name “is an acronym for Really Simple Syndication” and that “RSS is a dialect of XML,” requiring every document’s root <rss> element to declare version=“2.0”; the RSS Advisory Board has published this version since 2009.

First seen 2004 · Peaked 2007 · Retains 18% of peak Web fundamentals

S

Scaled content abuse

Generating many pages mainly to manipulate search rankings rather than help users, usually producing large volumes of unoriginal, low-value content no matter how it’s made. Google names using generative AI to create many pages without adding value, scraping feeds or search results to generate pages, and stitching content from other pages, as examples; Google introduced the policy on March 5, 2024, building on its earlier rule against automatically generated content.

Spam and black hat

Schema markup

Practitioner shorthand for structured data written in the schema.org vocabulary, embedded in a page’s HTML so search engines can parse what the page is about. Google’s own documentation almost always says “structured data” rather than “schema markup,” and treats its own Search Central pages, not schema.org’s, as definitive for what Google Search supports.

Structured data and entities Free SEO Chrome extension →

Schema.org Current · 100%

A shared vocabulary of types and properties, published at schema.org, that site owners use to mark up structured data so search engines can parse page content consistently. Google, Bing and Yahoo launched Schema.org on June 2, 2011, as a common vocabulary across search engines; schema.org’s own history also credits Yandex as a fourth founding company.

First seen 2011 · Peaked 2026 · Retains 100% of peak Structured data and entities

Scraped content In use · 86%

Content taken from other sites, often by automated means, and republished mainly to manipulate search rankings rather than to serve readers something new. Google names republishing without adding original value or citing the source, lightly rewriting text with synonyms, and reproducing another site’s content feed as abuse, while Bing separately warns that even light rewriting without new insight counts as scraping.

First seen 2006 · Peaked 2017 · Retains 86% of peak Spam and black hat

Search algorithm In use · 77%

The automated process a search engine uses to rank pages and other content for a query, weighing signals such as relevance, quality and usability. Google says its algorithms weigh many factors and signals about a query — including the words used, page relevance and usability, and a source’s expertise — and every proposed change goes through rigorous testing before launch.

First seen 2004 · Peaked 2015 · Retains 77% of peak Algorithms and updates

Search Console Google Search Console In use · 78%

A free tool from Google that shows how a site performs in Google Search, including indexing status, search traffic and technical issues Google finds while crawling it. Search Console emails site owners when Google finds new issues, and its Performance report counts clicks, impressions and average position for each query and page in Search results.

First seen 2006 · Peaked 2021 · Retains 78% of peak Analytics and rank tracking

Search engine In use · 69%

A software system that crawls, indexes and ranks web content, then returns matches for whatever a person types or speaks as a query. MDN Web Docs describes a search engine’s process in three steps: crawling the web by following links, indexing the content found, and searching that index to find and rank pages for a query.

First seen 2004 · Peaked 2007 · Retains 69% of peak Search fundamentals

Search engine index Fading · 56%

The database of crawled web pages and other content that a search engine builds and searches to return results for a query. Google likens its Search index to “the index in the back of a book,” with an entry for every word on every page it indexes, says crawlers build most of it, and puts its size at “well over 100,000,000 gigabytes.”

First seen 2004 · Peaked 2007 · Retains 56% of peak Search fundamentals

Search engine marketing In use · 69%

The practice of promoting a site through paid placements in search results, typically pay-per-click ads bought through a platform such as Google Ads. Google Ads shows these ads on the Google Search Network, above or below results on Google Search and on search partner sites and apps. Search Engine Land’s Danny Sullivan wrote in 2010 that he had proposed the term in 2001 as an umbrella covering SEO and paid listings, and that many people had since come to use it for paid search alone.

First seen 2004 · Peaked 2012 · Retains 69% of peak Search fundamentals

Search engine ranking Fading · 47%

A page’s position in a search engine’s results for a given query, expressed as a numbered place such as first or tenth. Google’s automated ranking systems weigh many signals to order pages, and Google says it personalizes some results — for example by factoring in a searcher’s location or search history — so the same query can rank a page differently for different people.

First seen 2005 · Peaked 2007 · Retains 47% of peak Search fundamentals

Search engine results In use · 86%

The listings and other result blocks a search engine returns for a query, as distinct from the page that displays them, the SERP. Google’s Search Quality Rater Guidelines use “result” for a result block together with its landing page, and say a block “may display information in the block itself or contain links, or may do both”; the unpaid listings among them are organic results.

First seen 2004 · Peaked 2007 · Retains 86% of peak Search fundamentals

Search history Current · 93%

The record of a person’s past search queries, kept in their account and sometimes used to personalize the results a search engine shows them. Google says people can see when their search history affected a ranked result through its “About this result” feature, and can review or delete saved search activity in their Google Account’s My Activity.

First seen 2005 · Peaked 2025 · Retains 93% of peak Search fundamentals

Search intent Current · 100%

The goal behind a search query, which Google's Search Quality Rater Guidelines frame as user intent, in categories including Know, Do, Website and Visit-in-Person. The guidelines describe a Know query as seeking information, a subtype called Know Simple as seeking one short factual answer, a Do query as wanting to accomplish a goal or activity, a Website query as wanting one specific page, and a Visit-in-Person query as wanting a nearby business or place.

First seen 2011 · Peaked 2026 · Retains 100% of peak Keyword research and intent

Search operators

A word or symbol, such as site: or filetype:, added to a query to refine or narrow what a search engine returns. Google documents operators such as site:, filetype:, imagesize: and src:, and recommends Search Console’s URL Inspection tool instead for debugging, since indexing and retrieval limits constrain what operators can reliably show.

Search fundamentals

Search query

The text, image or other input someone types or speaks into a search box to run a search. Google’s Search Quality Rater Guidelines note that queries may be spoken, typed, pasted or drawn from a camera or app, and that the same words can carry more than one meaning or intent.

Search fundamentals

Search term Fading · 50%

The exact word or phrase a person types or speaks into a search box, as distinct from any keyword an advertiser has chosen to target. Google Ads Help’s search terms report lists these actual queries beside the keyword that matched each one, since broad or phrase match types often let a keyword trigger ads on search terms that differ from it.

First seen 2004 · Peaked 2012 · Retains 50% of peak Keyword research and intent

Search visibility Current · 100%

A practitioner metric for how often and how prominently a site’s pages appear across search results for a set of tracked keywords. Tools calculate it from data such as Search Console’s impressions and average position, or from tracked rankings across a keyword list, so the exact formula and scale differ by tool and no single definition is standard.

First seen 2004 · Peaked 2026 · Retains 100% of peak Analytics and rank tracking

Search volume In use · 76%

An estimate of how many times a keyword is searched over a given period, most often expressed as an average number of monthly searches. Google Ads’ Keyword Planner defines the figure as an average over a chosen month range, 12 months by default, for a selected location and network, and says the resulting statistics are rounded rather than exact.

First seen 2007 · Peaked 2021 · Retains 76% of peak Keyword research and intent

Secure Sockets Layer

The predecessor protocol to TLS for encrypting a connection between a client and a server, now prohibited by the IETF in every version. Netscape released SSL 3.0, its last version, in 1996; RFC 6101, filed Historic, records that version and says the protocol “was never formally published by the IETF, except in several expired Internet-Drafts.” RFC 7568 separately says SSL 3.0’s encryption is “comprehensively broken” because of the POODLE attack, so a server still offering it fails a modern handshake.

Web fundamentals

Self-serving reviews

Google's name for a review of a business that appears on that same business's own website, added directly or through an embedded third-party widget. Google introduced the rule in a September 2019 blog post and stopped showing star review rich results for LocalBusiness and Organization pages that control their own reviews, though a site doesn't need to remove the markup and faces no manual action just for having it.

Local SEO

Semantic search Fading · 56%

Search that matches results to the likely meaning and intent behind a query, not only its literal keywords, for example by resolving synonyms or related concepts. Google says it builds language models to interpret a query’s intent and runs a synonym system that can match relevant pages even when they do not contain the exact words a searcher used.

First seen 2005 · Peaked 2014 · Retains 56% of peak Search fundamentals

Semantic SEO

The practice of structuring content around a topic’s meaning, entities and related concepts, instead of an exact-match keyword, so it aligns with how search engines interpret a query’s intent. Google’s SEO Starter Guide says its language-matching systems can connect a page to a query even when the page doesn’t use the query’s exact words, and Google names meaning, built partly on a synonym system, as one of Search’s key ranking signals.

On-page and content

Semantic triples

The subject-predicate-object structure that states a single fact in RDF and other linked-data formats, such as a page having an author, or a recipe having a cook time. The W3C’s RDF specification defines this structure formally as an “RDF triple” — subject, predicate, then object — and schema.org, the vocabulary behind most of Google’s structured data, is built on that same underlying RDF data model.

AI search and GEO

Sentiment analysis Current · 97%

The use of natural language processing to classify the opinion in a piece of text, such as a customer review, as positive, negative or neutral. Google Cloud's Natural Language API scores text this way to gauge a writer's attitude, and Google's own review system for service businesses separately rates individual aspects of a review as positive or critical feedback.

First seen 2006 · Peaked 2018 · Retains 97% of peak Local SEO

SEO search engine optimization Current · 90%

The practice of improving a site so it is easier for search engines to crawl, index and understand, increasing its visibility in unpaid search results. Google’s SEO Starter Guide says there are no secrets that automatically rank a site first, and Google warns that techniques violating its spam policies can lower a site’s presence in Google or get it removed from the index.

First seen 2004 · Peaked 2006 · Retains 90% of peak Search fundamentals

SEO agent

An AI agent, built to plan and carry out multi-step tasks with limited supervision, applied specifically to SEO work such as auditing a site or monitoring rankings. OpenAI describes agents generally as systems that can “plan and complete tasks using tools,” working with other agents and keeping context across steps — capabilities an SEO agent narrows to site audits, content checks or rank tracking instead of open-ended work.

AI search and GEO

SEO audit

A review of a site’s pages and configuration against the factors a search engine documents as required or recommended, done to find problems that may be limiting visibility. Google frames these factors in three sections, “technical requirements,” “spam policies” and “key best practices,” and says meeting them does not guarantee that a page gets crawled, indexed or served.

Technical SEO Technical SEO audit →

SEO automation

The use of scripts or software to perform SEO tasks, such as generating pages, submitting URLs or pulling ranking data, without a person doing each step by hand. Google’s spam policies treat automated page generation as scaled content abuse when its primary purpose is manipulating rankings rather than helping users, regardless of whether generative AI, scraping or other automated methods created the pages.

Analytics and rank tracking

SEO content

Content created or shaped so it can rank in and draw visitors from organic search results, spanning formats from blog posts to product and landing pages. Google says SEO “can be a helpful activity when it is applied to people-first content,” and advises creators against “search engine-first” content made mainly to gain rankings.

On-page and content

SEO copywriting Obsolete · 7%

The craft of writing on-page text, such as headlines, product copy and calls to action, that both persuades a reader and gives search engines relevant, well-matched language to index. Google’s SEO Starter Guide asks for text that is easy to read, well organized and free of mistakes, and Google’s spam policies prohibit keyword stuffing, filling a page with keywords to manipulate rankings.

First seen 2006 · Peaked 2012 · Retains 7% of peak On-page and content

SEO-friendly URL

A URL built from readable words related to a page’s content, rather than random IDs or unnecessary parameters, in what Google calls a descriptive URL. Google’s SEO Starter Guide says parts of a URL can appear as breadcrumbs in search results, so words useful to users belong in the path; Google’s URL structure guidance separately warns that parameters such as session IDs and referral codes can multiply a site’s URLs and complicate crawling.

Technical SEO

SEO monitoring

The ongoing practice of tracking a site’s rankings, traffic, technical health and search visibility to catch changes as they happen. Search Console itself supports this by emailing site owners whenever Google finds a new issue, and Google recommends checking the account periodically, such as monthly or after content changes, to confirm the data stays stable.

Analytics and rank tracking

SEO reporting

The practice of compiling a site’s search performance data into a document or dashboard that practitioners share with a client or team. Google’s own reporting tool, Data Studio, connects to data sources and turns them into customizable, shareable dashboards, while Search Console supplies the underlying clicks, impressions and position figures such reports typically present.

Analytics and rank tracking

SEO tool Current · 99%

Software that helps a practitioner research, monitor or report on a site’s search performance, such as checking rankings, crawling pages or auditing technical issues. Google Search Central says it doesn’t evaluate third-party tools, that none has access to Google’s internal ranking data, and recommends Search Console, its own first-party tool, for data that comes directly from Google Search.

First seen 2006 · Peaked 2025 · Retains 99% of peak Analytics and rank tracking

SERP search engine results page Fading · 51%

The page a search engine returns for a query, assembled from individual result blocks such as text, image, video and rich results. Google’s Visual Elements gallery catalogs the common building blocks of this page — text, rich, image and video results, plus exploration features — noting their look can vary by device, country and query language.

First seen 2006 · Peaked 2012 · Retains 51% of peak Search fundamentals Rank tracking →

SERP feature

Any element on a Google Search results page other than the standard organic text listings, such as a rich result or a knowledge panel. Google itself doesn’t use this umbrella term; its own documentation calls these “visual elements” and, when built from structured data, “rich results.”

SERP features

SERPs search engine results pages Fading · 36%

The plural of SERP, used by practitioners as shorthand for search results pages in general or for the results landscape across many queries. Google’s Search Quality Rater Guidelines define one SERP as the page a search engine shows for a query, made up of result blocks; practitioners extend the acronym’s plural to talk about rankings or results across many different searches at once.

First seen 2004 · Peaked 2005 · Retains 36% of peak Search fundamentals

Server-side rendering

The practice of generating a page’s HTML on the server and sending complete markup to the browser, instead of building the page in the browser with JavaScript. MDN Web Docs says the approach lets crawlers read a page’s content without executing JavaScript, though major search engines can render scripts themselves; Google says server-side rendering or pre-rendering is still worthwhile because it makes a site faster and not every bot can run JavaScript.

Technical SEO Technical SEO audit →

Service area

The set of cities, postal codes or other named areas — rather than a radius — that a service-area or hybrid business tells Google it serves. Google lets a business list up to 20 service areas and says the overall area shouldn't usually reach farther than about two hours' driving time from where the business is based.

Local SEO

Service-area business

A business type in Google Business Profile that travels to its customers or delivers to them instead of receiving them at its own address. Google tells these businesses to remove their address if customers are not served there and to list up to 20 service areas, such as cities or postal codes, not a radius; the overall area should usually stay within about two hours’ drive of the business’s base.

Local SEO Local SEO →

Session ID

A unique value a server assigns to track one visitor’s activity across multiple requests, sometimes appended to a page’s URL as a query parameter. Google’s URL structure guidance names session IDs in URLs as a cause of near-infinite sets of duplicate addresses, and tells site owners to use cookies instead wherever possible or to block the affected URLs in robots.txt.

Technical SEO

Seven-pack

A practitioner nickname for the version of Google's local pack that showed seven businesses before Google narrowed it to three. Search Engine Roundtable reported on August 7, 2015, that Google had replaced the seven-result local block with a three-result one. Google says it ranks local results mainly on relevance, distance and popularity.

Local SEO

Sitelinks Current · 98%

Two or more links from the same domain that Google clusters together beneath a single text result, pointing to other pages on that site. Google says sitelinks are automated, generated by analyzing a site’s link structure and shown only when they’re judged useful to the user; a logical site structure and concise, relevant internal-link anchor text improve their quality.

First seen 2010 · Peaked 2015 · Retains 98% of peak SERP features

Sitemap Fading · 48%

A file that lists a site’s pages, videos and other files for search engines, so they can discover them more efficiently than by following links alone. Google accepts the sitemaps.org protocol’s XML, RSS or Atom, and plain-text formats; it says a sitemap doesn’t guarantee every listed URL gets crawled or indexed, but a site may want one if it is large, new with few external links, or rich in image, video or News content, and many content management systems create one automatically.

First seen 2005 · Peaked 2005 · Retains 48% of peak Technical SEO

Site migration

A change to a site’s domain, URL paths or hosting infrastructure, called a site move in Google’s own guidance, that requires search engines to find and re-index the new addresses. Google publishes separate guides for moves that change URLs, such as domain or HTTP-to-HTTPS changes, and moves that only change hosting; it says a permanent redirect loses no PageRank, and that Googlebot processes a move URL by URL rather than all at once.

Technical SEO

Site reputation abuse

The practice of publishing third-party content on an established site mainly to exploit that host’s ranking signals, which Google’s spam policies prohibit. Google announced the policy on March 5, 2024, and it took effect on May 5, 2024. Google says hosting third-party content is not in itself a violation, and its human reviewers weigh how far the host controls the content’s presentation, quality and authorship.

Spam and black hat

Social media In use · 76%

Websites and apps built around user-created profiles, where people publish content and connect with others through following, sharing and commenting. Google’s structured data documentation covers social platforms with SocialMediaPosting markup, “the parent type of DiscussionForumPosting,” and lets a site’s Organization markup list a social media profile page as a sameAs URL, one signal Google uses to connect a site to its identity elsewhere on the web.

First seen 2006 · Peaked 2022 · Retains 76% of peak Web fundamentals

Soft 404

A URL that returns a successful HTTP status but whose page content reads to Google as an error message or an empty page. Search Console reports a soft 404 for such a URL, and Google recommends returning a real 404 code for pages that truly don’t exist, or adding content that shows Google the page isn’t an error.

Technical SEO

SpamBrain

An AI-based system Google has used since 2018 to detect and address spam and other behavior that violates its spam policies. Google said SpamBrain caught 200 times as many spam sites in 2021 as when Google started fighting webspam nearly two decades earlier, and flagged almost six times more spam sites that year than in 2020.

Algorithms and updates

Spam policies

Google’s published policies defining web search spam: techniques that deceive users or manipulate Google’s Search systems, including generative AI responses, into featuring content that shouldn’t otherwise qualify. Google’s automated systems catch most violations, and, when needed, a human reviewer’s findings can lead to a manual action; a site found in violation may drop in rankings or disappear from results altogether.

Spam and black hat

Spam Score

Moz’s proprietary metric estimating, as a percentage, how similar a site is to others Moz has found penalized or banned by Google. Moz groups scores into low (1–30%), medium (31–60%) and high (61–100%), says a score doesn’t mean a site is spammy but is a guide for further investigation, and updates it quarterly from 27 signals.

Links and authority

Splash page

An introductory page a visitor sees before a site’s actual homepage, often used for branding, an age check or a language choice. Google Search Essentials says a page needs crawlable, indexable content to appear in Search results at all, a requirement that applies to a splash page at a site’s root URL just as it does to any other page.

Technical SEO

srcset

An HTML attribute on <img> and <source> elements that lists alternate image files, each tagged with a width or pixel density, for the browser to pick from. WHATWG’s HTML Standard defines width and pixel-density descriptors for each listed source; with width descriptors the browser also needs the sizes attribute to pick a match, while pixel-density descriptors let the browser match the screen’s density directly, so a lower-resolution screen downloads a smaller file.

Page experience

SSL certificate

A digital certificate a server presents to prove its identity and set up an encrypted connection, commonly still called by the name of SSL, the protocol TLS replaced. RFC 8446 has a TLS server send this certificate, typically in the X.509 format, in a Certificate message during the handshake so the client can authenticate it before trusting the connection; despite the everyday name, the certificate secures a TLS connection, since SSL itself is deprecated.

Web fundamentals

Star rating Fading · 55%

The average of a business's customer ratings, shown as a number of filled stars on a scale of 1 to 5 on Google and similar local listings. Google calculates the score as the average of all ratings published for a place and says a new rating can take up to two weeks to show; the same average appears in schema.org AggregateRating markup, which defaults to a 5-point scale unless a page sets its own.

First seen 2007 · Peaked 2018 · Retains 55% of peak Local SEO Local SEO →

Static content In use · 64%

Content a server sends to the browser exactly as it’s stored, without generating or altering it for each individual request. MDN Web Docs contrasts this with dynamic content, which an application server assembles per request, often by filling a template from a database, and calls a purely static site the easiest type of site to set up.

First seen 2005 · Peaked 2010 · Retains 64% of peak Technical SEO

Store locator Fading · 38%

A page or tool on a business's website that helps customers find its nearby physical locations, typically through an address search or an embedded map. Google Maps Platform's own store-locator codelabs combine the Maps JavaScript API, Place Autocomplete and the Distance Matrix service to show a visitor the closest locations from a business's own location data.

First seen 2009 · Peaked 2015 · Retains 38% of peak Local SEO

Street View Fading · 36%

A Google Maps and Google Earth feature that shows panoramic, street-level photographs of a location so a viewer can look around as if standing there. Google says Street View combines billions of panoramic images from Google and outside contributors, and a viewer can browse historic imagery from earlier dates where it's available.

First seen 2007 · Peaked 2011 · Retains 36% of peak Local SEO

Structured citation

A local citation whose name, address and phone number sit in distinct database fields — such as a directory's listing form — rather than written as plain text. Google says it compiles Google Business Profile details partly from licensed third-party data and crawled web content.

Local SEO

Structured data Current · 100%

A standardized format for providing information about a page and classifying its content, such as a recipe’s ingredients and cook time. Google can use it to classify a page and, in some cases, show the page as a rich result. Google says most Search structured data uses schema.org vocabulary in the JSON-LD, Microdata or RDFa format, and treats its own documentation, not schema.org’s, as definitive for what Google Search supports.

First seen 2004 · Peaked 2026 · Retains 100% of peak Structured data and entities Technical SEO audit →

Structured review

A customer review encoded with schema.org's Review or AggregateRating markup, giving search engines a machine-readable rating value, author and date rather than plain text. Google requires specific properties, such as reviewRating and itemReviewed, before it will treat marked-up content as eligible for a star review rich result, and schema.org defines Review itself as a review of an item such as a restaurant, movie or store.

Local SEO

Surface coverage

SEO Bandwagon's own metric for whether a keyword appears on the surfaces Google indexes for a business, and whether it matters which surface carries it. SEO Bandwagon's Periodic Table of SEO lists it as element Sc and describes it as a generalization of whether reviews help a business rank, widening the question from reviews to the surfaces Google indexes.

Local SEO

System prompt

The instructions a developer sets before a conversation starts to fix an AI model’s role, tone or rules, held apart from and given priority over the user’s own messages. OpenAI’s API gives instructions passed this way priority over anything in the user’s own prompt, and Anthropic’s prompt-engineering documentation says setting a role in the system prompt measurably changes a model’s behavior and tone, even in a single added sentence.

AI search and GEO

T

Table of contents

A list of links near the top of a long page, each pointing to one of its sections, that lets a reader jump straight to the part they want. Google said in a 2009 blog post that it could algorithmically add links to a long page’s sections inside its snippet, for queries where those links would be useful, and that clearly named sections with a table of contents linking to their anchors make them more likely.

On-page and content

Taxonomy

The scheme a site uses to sort its content into categories, subcategories and tags, usually reflected in its URL paths and navigation menus. Google’s SEO Starter Guide says grouping topically similar pages into directories can help it learn how often a section’s content changes and crawl it accordingly, though it says most sites will be understood regardless of how they’re organized.

Technical SEO

Technical SEO

The practice of preparing a site’s code, markup and server configuration so that search engines can crawl, render and index it correctly. Google Search Essentials groups the minimum a page needs to appear in Search under a “technical requirements” heading, separate from its spam policies and key best practices, and most sites meet them without any special work.

Technical SEO

Ten-pack

A practitioner nickname for a Google local results block that listed ten businesses beside a map, more than today's standard local pack. Search Engine Land reported on April 1, 2009, that Google was showing this "10-pack" of local results with a map even for generic searches such as "restaurants" that named no city. Google says it ranks local results mainly on relevance, distance and popularity.

Local SEO

Thin affiliation

Publishing pages with affiliate links whose product descriptions and reviews are copied straight from the merchant, adding no original content or value of their own. Google treats a page as thin if it’s part of a program distributing the same content across a network of affiliates without added value, often producing cookie-cutter pages repeated across a site or domains; Google says good affiliate sites instead add original reviews, testing or comparisons.

Spam and black hat

Thin content Fading · 49%

A page judged to add too little unique value for a reader, typically because it repeats, thinly rewrites or automates material that existing pages already cover better. Search Console lists “thin content with little or no added value” as a manual action, giving thin affiliate pages, scraped content and doorways as examples; Google’s spam policies cover the same ground under thin affiliation and scaled content abuse.

First seen 2009 · Peaked 2018 · Retains 49% of peak On-page and content Technical SEO audit →

Third-party reviews

Customer reviews of a business that a platform such as Google displays after collecting them from a separate, independent review site. Google says a Google Business Profile may display reviews gathered by trusted outside sites, such as travel or local review sites, but an owner can't choose which site a review comes from or stop one from appearing, and must contact the originating site to dispute it.

Local SEO

Time on page Current · 90%

The length of time visitors spend on a single page during a visit, a metric several analytics tools report but Google Analytics 4 does not. GA4 instead reports Average engagement time, built from an engagement_time_msec value that a browser tab sends only while in the foreground, summed per user or session rather than tied to one page.

First seen 2008 · Peaked 2016 · Retains 90% of peak Analytics and rank tracking

Time to First Byte

A metric that times the gap between a browser starting to navigate to a page and the first byte of the server’s response arriving. TTFB sums redirect time, service worker startup, DNS lookup, connection and TLS negotiation, and request time up to the first byte. web.dev rates 0.8 seconds or less as good, more than 1.8 seconds as poor, and anything between as needing improvement, and notes TTFB is not a Core Web Vitals metric but precedes Largest Contentful Paint.

Page experience Free SEO Chrome extension →

Title tag Obsolete · 24%

The <title> HTML element, which the HTML Standard defines as a page’s title, shown in the browser tab and usually as the headline of its Google result. WHATWG’s HTML Standard says authors should write titles that identify a document even out of context, such as in search results. Google builds its title link from several sources, and its August 2021 post said title-element text was used more than 80% of the time and that titles generally no longer changed per query.

First seen 2005 · Peaked 2006 · Retains 24% of peak On-page and content Free SEO Chrome extension →

Token

The atomic unit of text, typically a word, part of a word or a single character, that a language model reads and generates one piece at a time. Google’s Machine Learning Glossary gives the phrase “dogs like cats” as an example of three word tokens, and notes a model’s tokenizer may instead split text into subwords, such as splitting “taller” into the root “tall” and the suffix “er.”

AI search and GEO

Topical authority

A site or author’s perceived depth of expertise on a subject, built by covering it comprehensively enough that searchers and other sites treat it as a trusted reference. Google’s self-assessment questions for helpful content ask whether a page gives a substantial, complete or comprehensive description of a topic and whether it demonstrates firsthand expertise, the same depth-of-coverage idea practitioners describe as topical authority.

On-page and content

Top-level domain In use · 71%

The final label in a domain name, such as .com or .uk, assigned and delegated within the Domain Name System’s root zone. IANA’s Root Zone Database lists the delegation details of every top-level domain, including generic top-level domains such as .com and country-code top-level domains such as .uk, and RFC 1591 set the original rules for assigning and delegating them.

First seen 2004 · Peaked 2012 · Retains 71% of peak Web fundamentals

Top Places List

A Google Search rich result that shows which independent, editorially curated "top places" lists — such as a "Top 10" roundup — mention a physical-location business. Google requires the list to be genuine, independent and unsponsored, not built from templated or automated text, and free of vulgar language; a site can opt its own lists out of the feature.

Local SEO

Tracking code Fading · 52%

The snippet of JavaScript a site owner adds to their pages so a platform such as Google Analytics can collect visit data from that page. Google’s own help pages call this snippet the tracking code, and say it collects pseudonymous information, such as which pages a visitor visited and their browser type, each time a page loads.

First seen 2007 · Peaked 2015 · Retains 52% of peak Analytics and rank tracking

Traffic source Fading · 55%

The channel or origin, such as a search engine, another website or a direct visit, that Google Analytics and similar platforms credit for sending a visitor to a site. GA4 records this as session source and medium and rolls sessions up into a default channel group, such as Direct, Organic Search or Referral, based on rule-based definitions Google documents and updates.

First seen 2008 · Peaked 2012 · Retains 55% of peak Analytics and rank tracking

Transformer (AI model) Current · 100%

A neural network architecture that uses self-attention to weigh the relevance of every other input element, rather than reading a sequence strictly in order. Eight Google researchers introduced the architecture in a 2017 paper, and Google’s own Machine Learning Glossary credits it as “developed at Google”; it now underlies most large language models, including those built by other companies.

First seen 2019 · Peaked 2026 · Retains 100% of peak AI search and GEO

TrustRank Obsolete · 22%

A technique proposed in a 2004 research paper that scores a page by how many links separate it from a small set of trusted seed pages. Stanford researchers Zoltán Gyöngyi and Hector Garcia-Molina wrote the paper with Yahoo’s Jan Pedersen, proposing that a human expert evaluate a small seed set and then propagate trust across the web’s link structure from there. Pages farther from any seed page are treated as more likely to be spam.

First seen 2005 · Peaked 2007 · Retains 22% of peak Algorithms and updates

U

Unclaimed listing

A business listing that exists on a platform such as Google or Bing but hasn't been verified by an authorized owner or manager of the business. Google has an owner search Google Maps for the business, select "Claim this business," then complete a verification option to take control of it.

Local SEO

Unique visitors Obsolete · 24%

The count of distinct people who visited a site in a period, each counted once no matter how many sessions or pageviews they generated. Google Analytics 4 has no metric by this name; its closest replacement, Total users, counts the unique user IDs that triggered any event during the period.

First seen 2005 · Peaked 2005 · Retains 24% of peak Analytics and rank tracking

Universal search Fading · 49%

Google’s name for its 2007 move to blend results from Images, Video, News, Maps and Books into one set of web results, instead of separate silos. Google announced the change on May 16, 2007, saying it aimed to break down the walls that traditionally separated its various search properties.

First seen 2009 · Peaked 2015 · Retains 49% of peak SERP features

Unstructured citation

A local citation in which a business's name, address and phone number appear together in ordinary prose, such as a news article, rather than in a directory's structured fields. Google says it also compiles Google Business Profile details from crawled web content.

Local SEO

Unstructured review

A customer review that appears only as plain text or an unmarked embed, without the schema.org fields a search engine needs to parse it as a rating. Google's review-snippet guidelines require properties such as reviewRating and an item name before content is eligible for a star rich result, so a review lacking that markup can't trigger one even though a reader can still see it.

Local SEO

URL Uniform Resource Locator

A compact string, standardized by the WHATWG as a “universal identifier,” that names a web resource’s location and the scheme used to reach it. RFC 3986 calls the same concept a Uniform Resource Identifier and defines its generic syntax of scheme, authority, path, query and fragment; the WHATWG’s URL Standard aims to align that syntax with how browsers actually parse addresses. Google’s rater guidelines describe a URL simply as what a browser uses to find and display a page.

Web fundamentals

URL hijacking

A technique for stealing another page’s rankings by 302-redirecting a page the attacker controls to it, reported to have worked against Google’s older indexing systems. Search Engine Roundtable reported in 2011 that Google’s Matt Cutts said “way back in the mists of time we had things called 302 hijacks but I haven’t seen any attempts like that succeed in years.”

Spam and black hat

URL Inspection tool

A Search Console feature that reports how Google’s index sees one specific URL and lets an owner test whether a live version of it could be indexed. Google’s Search Console Help says the report covers structured data, canonical selection and a rendered screenshot of the page, and can request that a URL be crawled, though a passing live test does not guarantee that Google will index it.

Technical SEO

URL Rating

Ahrefs’s proprietary score, on a 100-point scale, showing the link-profile strength of one specific page rather than a whole domain. Ahrefs calculates it on PageRank-like principles — counting links, respecting nofollow, applying a damping factor — and says the scale is logarithmic, so moving from 20 to 30 is far easier than from 70 to 80.

Links and authority

URL slug Fading · 54%

The short, readable part of a URL that identifies one specific page, usually the final segment after the domain and any category path. MDN Web Docs calls a slug the readable, identifying segment of a URL, typically at the very end; Google’s SEO Starter Guide says parts of a URL can appear as breadcrumbs in search results, so descriptive words help users judge a page before clicking.

First seen 2010 · Peaked 2012 · Retains 54% of peak Technical SEO

Usability In use · 69%

A measure of how effectively, efficiently and satisfyingly a person can use a product or interface to reach a specific goal. The W3C’s Web Accessibility Initiative cites the ISO 9241-11 standard, which defines usability as the extent to which a product lets specified users “achieve specified goals effectively, efficiently and with satisfaction.” On the web, usability is typically checked with user testing.

First seen 2004 · Peaked 2012 · Retains 69% of peak Page experience

Usage data

Data a platform collects about how people interact with its product, such as clicks, queries, dwell time or navigation, as distinct from data users directly submit. A federal court’s August 2024 findings in the Google search antitrust case describe one such signal, Navboost, as a ranking system Google built by “memorizing user click data” from roughly 13 months of search activity, based on trial testimony from Google’s own engineers.

Analytics and rank tracking

User agent

The client software — a browser, crawler or other program — that sends an HTTP request, identified to the server by the User-Agent header RFC 9110 defines. Google says its crawlers identify themselves three ways — the User-Agent request header, the source IP address, and the reverse DNS hostname of that IP — since a user-agent string alone is easy to spoof; RFC 9110 itself warns that a client masquerading under another product’s name can’t be relied on to get that product’s tailored response.

Web fundamentals

User experience Current · 92%

The overall quality of interacting with a system such as a website, based on how intuitive, easy and satisfying it is for the person using it. MDN Web Docs describes UX as the study of how users interact with a system, aiming to make it intuitive and easy to use. Core Web Vitals score one part of user experience — loading, responsiveness and visual stability — and Google says its ranking systems use them.

First seen 2005 · Peaked 2025 · Retains 92% of peak Page experience

User testing Fading · 31%

The practice of observing representative users attempt real tasks on a product, to find where its design or wording causes confusion or friction. The W3C’s Web Accessibility Initiative describes formal usability testing as following set protocols that gather both numeric and descriptive data by watching representative users work through specific tasks, sometimes narrating their thinking aloud; participant backgrounds depend on the target audience.

First seen 2008 · Peaked 2012 · Retains 31% of peak Page experience

V

Vanity URL

A short, branded URL that marketers put in place of a longer or less memorable address, usually redirecting visitors to the real destination. Google’s Campaign Manager 360 help gives the name a narrower, ad-tracking meaning: a 302 redirect through a virtual directory on the advertiser’s own site, used to count clicks on HTML emails.

Technical SEO

Vector database Current · 100%

A database built to store numerical vector embeddings and quickly find the ones most similar to a query vector, rather than to match exact values. OpenAI’s embeddings guide recommends a vector database for searching over many vectors quickly, the role it plays in retrieval-augmented generation: the original RAG paper describes retrieving from “a dense vector index” before a language model composes its answer.

First seen 2023 · Peaked 2026 · Retains 100% of peak AI search and GEO

Vertical search Fading · 30%

A search engine or search feature limited to one category of content or commerce, such as shopping, travel or local listings, instead of the general web. The Federal Trade Commission’s 2013 statement on Google’s search practices described general-purpose engines like Google as distinct from “vertical” engines that “focus on narrowly defined categories of content such as shopping or travel.”

First seen 2005 · Peaked 2007 · Retains 30% of peak Search fundamentals

Virtual assistant Current · 98%

Software, reached by voice or text, that carries out tasks such as answering questions, setting reminders or giving directions on a person’s behalf. Google documents Google Assistant as handling actions such as asking questions, making calls, sending texts, scheduling reminders and giving directions.

First seen 2008 · Peaked 2025 · Retains 98% of peak AI search and GEO

Virtual office

A rented mailing address a business uses without actually operating from that location, as opposed to a staffed physical office. Google Business Profile guidelines say a location like this isn't eligible for a profile, and that a service-area business can't list one as its base unless it's staffed during business hours.

Local SEO

Visit-in-Person query

Google's Search Quality Rater Guidelines term for a search, such as "gas stations" or "car repair shop," that clearly asks for nearby businesses or places. The guidelines contrast this with queries that show no such intent, such as "how tall is Mount Everest," and say some queries could go either way, since some searchers want nearby results and others don't; raters are told to use common sense about a query's possible visit-in-person intent.

Local SEO

Visual search

Search that takes a photo or image as the query instead of typed or spoken words, matching it to visually or contextually similar results. Google Lens, Google’s tool for this, lets someone search with a camera or an existing image to identify objects, translate text or find visually similar products.

Search fundamentals

Voice search In use · 75%

Search run by speaking a query aloud to a device instead of typing it, using speech recognition to turn the audio into text a search engine can process. Google Assistant, one voice platform, lists asking questions among its core actions. On smart speakers, it can answer news queries by reading aloud up to three articles marked up with Google’s speakable structured data.

First seen 2007 · Peaked 2020 · Retains 75% of peak Search fundamentals

W

Web directory Fading · 45%

A site that organizes other websites into human-edited categories, rather than finding them by crawling and ranking the way a search engine does. Google’s spam policies name “low-quality directory or bookmark site links” as an example of link spam, which is why practitioners distinguish a small number of selective, curated directories from the mass-submission kind.

First seen 2004 · Peaked 2005 · Retains 45% of peak Links and authority

Web presence management Fading · 59%

An industry term for the ongoing practice of keeping a business's information consistent across its website, listings, social profiles and reviews. Google says it compiles Google Business Profile details from a business's own edits, crawled web content, licensed third-party data and user contributions; its sourcing guidance doesn't say inconsistent information across these surfaces hurts a business, so a practitioner's belief that it does is not a documented Google factor.

First seen 2015 · Peaked 2015 · Retains 59% of peak Local SEO

Web reference

An industry term for any online mention of a business that a search engine can crawl, whether or not it's formatted as a formal citation. Google says it compiles Google Business Profile details partly from crawled web content.

Local SEO

Web server Fading · 59%

The combination of hardware that stores a site’s files and HTTP server software that understands URLs and HTTP well enough to deliver those files to a browser. RFC 9110 defines an HTTP server generically as a program that accepts connections to service HTTP requests; MDN Web Docs distinguishes a static web server, which returns hosted files unchanged, from a dynamic one, which fills a template from a database before responding.

First seen 2004 · Peaked 2005 · Retains 59% of peak Web fundamentals

Website In use · 86%

A group of World Wide Web pages, usually linked to each other, that an individual, company, institution or organization makes available online under its control. Google’s Search Quality Rater Guidelines note that raters also use “website” for a major, independently run section of a larger site, such as a company’s finance or sports subdomain, rather than only for an entire domain under one owner.

First seen 2004 · Peaked 2017 · Retains 86% of peak Web fundamentals

Website navigation Fading · 34%

The menus, links and other on-page elements that let a visitor move between a site’s pages, and that a crawler can follow to reach them too. Google’s ecommerce site-structure guidance says these links let it infer a page’s relative importance from how many clicks reach it, and recommends plain <a href> links over JavaScript-only navigation so Googlebot can find every page without relying on a search box.

First seen 2005 · Peaked 2014 · Retains 34% of peak Technical SEO

Website structure

The way a site’s pages are organized and connected through links, from the homepage down to individual pages, usually mirrored in its URL and folder layout. Google’s ecommerce site-structure guidance says it generally infers a site’s structure from the links between pages rather than from URL patterns, and that a page’s relative importance rises with the number of internal links pointing to it.

Technical SEO

Website traffic In use · 77%

The visits a website receives, typically measured in sessions, users or pageviews over a period of time. Google Analytics groups this traffic into acquisition reports by channel, such as Organic Search, Direct or Referral, so a site owner can see which sources send visitors.

First seen 2004 · Peaked 2005 · Retains 77% of peak Analytics and rank tracking

White hat SEO Fading · 34%

Search engine optimization tactics that comply with a search engine’s published guidelines while working to improve rankings. Google’s Search Essentials call these “key best practices” — creating people-first content and using the words searchers would use — rather than a hat category, alongside technical requirements and spam policies a site must also meet.

First seen 2004 · Peaked 2006 · Retains 34% of peak Spam and black hat When SEO Was Spam →

WHOIS

A protocol, standardized in RFC 3912, for querying who registered a domain name, an IP address block or an autonomous system number. ICANN calls WHOIS a service, not an acronym, that identifies who is responsible for a domain name or IP address; for generic top-level domains, it required the Registration Data Access Protocol to replace WHOIS on January 28, 2025, after offering RDAP as an alternative since 2019.

Web fundamentals

Word count In use · 75%

The number of words on a page, a rough measure of length that some practitioners track as a proxy for how thoroughly a page covers its topic. Google’s SEO Starter Guide says the length of a page’s content doesn’t by itself affect ranking, and sets no minimum or maximum word count to target.

First seen 2011 · Peaked 2020 · Retains 75% of peak On-page and content

X

x-default

The hreflang value that marks a page as the fallback Google Search shows a searcher whose language or region doesn’t match any of the page’s other hreflang-tagged versions. Google specifically recommends x-default for language or country selector pages and auto-redirecting homepages, set the same way as any other hreflang annotation.

E-commerce and international

XHTML Extensible HyperText Markup Language

A W3C-standardized reformulation of HTML as an XML application, so that a document is well-formed by XML’s stricter parsing rules rather than HTML’s more forgiving ones. W3C marked its XHTML 1.0 recommendation “superseded” on March 27, 2018, pointing implementers to the HTML Standard instead; that standard no longer uses the name XHTML for HTML’s XML syntax, noting no equivalent term is used for the HTML syntaxes of MathML or SVG.

Web fundamentals

XML Extensible Markup Language

A W3C-standardized, text-based format for structuring data into a tree of custom-named elements, so both humans and machines can read it. The W3C’s XML 1.0 specification, now in its fifth edition, published November 26, 2008, calls XML “an application profile or restricted form of SGML” that describes “a class of data objects called XML documents”; formats such as RSS and XHTML are themselves XML applications.

Web fundamentals

XML sitemap Fading · 55%

A sitemap written in the XML format defined by the sitemaps.org protocol, listing a site’s URLs inside a structured <urlset> of <url> entries. The protocol requires a <loc> entry for every URL and limits each sitemap file to 50,000 URLs or 50MB uncompressed, so a larger site needs a sitemap index file listing multiple XML sitemaps instead of one.

First seen 2005 · Peaked 2010 · Retains 55% of peak Technical SEO

X-Robots-Tag

An HTTP response header that carries the same indexing and serving rules as the robots meta tag, for files where editing the page’s HTML isn’t possible. Google’s specification says this header is used to block indexing of non-HTML files such as PDFs, videos or images; multiple directives can combine in one response, and a directive can target one named crawler instead of applying to all of them.

Technical SEO

Y

Yahoo! Directory Fading · 31%

The human-edited, category-based directory of websites that Yahoo started with in the 1990s and retired in December 2014. Yahoo said in 2014 that it had started nearly 20 years earlier as a directory helping users explore the internet; by then the directory’s homepage sorted sites into 14 top-level categories, from Arts & Humanities to Society & Culture, with a link to suggest a site.

First seen 2004 · Peaked 2007 · Retains 31% of peak Links and authority

YMYL Your Money or Your Life

A category of topics where content could significantly affect a person’s health, finances or safety, or society’s welfare, as Google’s Search Quality Rater Guidelines define it. The guidelines say YMYL harm can reach the person viewing content, other people affected by that person, or society, and that raters must scrutinize clear YMYL topics most closely; Google says its systems give extra weight to strong E-E-A-T on these topics.

On-page and content

Z

Zero-click answer

An AI-generated response, such as an AI Overview, that fully answers a searcher’s question without a click to any source page. Google doesn’t use this term; its own AI-features documentation says these responses are designed to show supporting links and that clicks arriving from an AI Overview tend to be “higher quality,” meaning visitors spend more time on the destination site.

AI search and GEO

Zero-click search

A search in which the person’s need is fully met on the results page itself, without a click through to any website. Google doesn’t define or use the term; it says its features aim to connect people to information as quickly as possible, and describes showing answers such as a weather forecast directly on the results page.

SERP features

Browse by topic

Technical SEO 152

Crawling, indexing, rendering and the site architecture underneath them.

Local SEO 138

Google Business Profile, the map pack, citations and reviews.

How this glossary works

Every definition answers the literal question first, in plain English, then says how the thing works or why it matters.

233 of 640 terms carry a date: when Wikipedia’s SEO and web articles first used the term, the year they used it most, and how much of that use survives. A date needs at least 20 uses across 3 articles and 3 years, with a peak year of at least 5 uses across 2 articles. HTTP status codes and other fixed technical standards, such as HTML, URL and HTTP, are technical specifications and are not dated, because their meaning doesn’t drift the way community jargon does. The rest appear too rarely in Wikipedia’s SEO and web articles to date, or only as a common word that can mean something else there.

The dates come from the second edition of the corpus behind our study History of SEO Terms on Wikipedia, with its method: the original study articles plus 402 added, each article counted once and 2 off-topic articles left out, for 12,492 article-year snapshots of Wikipedia from 2004 to 2026. The study’s own 36 terms keep its published figures, measured on its first edition of 6,083 snapshots. Another 12 terms keep their first-edition dates, because the added articles use those words in other senses. Peak is the year a term was used most; retained is how much of that peak frequency survives in 2026. Obsolete means under 25% retained, fading under 60%, in use under 90%, current 90% and above.

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