Search Central LiveDeep Dive Europe 2026

Knowledge base v2.13.0 · Community edition · data through 2 October 2026

Area

Serving and ranking

How Google understands queries, retrieves and ranks results, tests and updates its systems, fights spam, and builds the results page, Discover and its features.

9 topics · 294 claims

Topics in this area 9

Across days 43

  1. Stage D2-C452 Day 2 · What is Structured Data and why we need it on the internet.

    Search results have moved from ten blue links to feature-rich, media-rich results because users wanted more.

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    Stage D1-C158 Day 1 · Welcome and opening keynotes

    Google said that even the classic ten-blue-links layout was settled only after millions of experiments, as part of using as much data as possible for product decisions.

  2. Stage D2-C521 Day 2 · What is Structured Data and why we need it on the internet.

    Structured data makes pages eligible to appear as rich results, Google's structured data talk said in its recap.

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    Stage D1-C122 Day 1 · session not recorded

    Check and focus on rich results for Google.

  3. Stage D2-C687 Day 2 · Deciding what goes in the index?

    Index selection uses the signals calculated earlier in indexing for each document it has to select or discard.

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    Stage D1-C205 Day 1 · How Search works and where's AI?

    Signals calculated for a page during indexing are stored in the index and used both to decide whether the page gets indexed and, later, for ranking.

  4. Stage D3-C006 Day 3 · Making sense of users' queries

    Google's first step in understanding almost any query is to detect its language, which tells Google roughly what content the user wants: a query in German suggests German content, a query in English English content.

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    Stage D2-C654 Day 2 · Calculating (some) signals

    In ranking, country and language signals help Google serve users the right content for their country and language.

  5. Stage D3-C007 Day 3 · Making sense of users' queries

    Query language detection works poorly when someone searches only for a brand name, such as Facebook or Google, because the query does not show which language the user wants results in.

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    Stage D1-C215 Day 1 · How Search works and where's AI?

    Serving starts with interpreting the query, which includes cleaning it up, detecting its language and expanding it.

  6. Stage D3-C011 Day 3 · Making sense of users' queries

    Google named Thai as a language that makes query understanding more complex because it does not separate words with spaces; the speaker added, hedging with 'apparently', that Thai uses spaces to separate sentences.

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    Stage D2-C320 Day 2 · Understanding what's on a page

    Text in languages written without spaces, such as Thai and Chinese, would end up in the index as long strings that might never be searched for, so Google segments it into words with statistical models built from other web content in that language.

  7. Stage D3-C013 Day 3 · Making sense of users' queries

    Google's query processing deliberately mirrors indexing: a query is transformed into something that can be matched against the index, and stop word removal is part of that transformation.

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    Stage D2-C321 Day 2 · Understanding what's on a page

    For languages written without spaces, such as Thai and Chinese, Google uses exactly the same word segmentation when indexing a page as when interpreting the user's query, because otherwise the query could not be matched against the index.

  8. Stage D3-C013 Day 3 · Making sense of users' queries

    Google's query processing deliberately mirrors indexing: a query is transformed into something that can be matched against the index, and stop word removal is part of that transformation.

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    Stage D2-C737 Day 2 · How does the index look like?

    A search query is broken into words with the same segmenter or tokenizer that Google used to build the index.

  9. Stage D3-C015 Day 3 · Making sense of users' queries

    Google said the difference between words and entities can be seen in Google Trends, where a term can be searched as words or as an entity (Trends calls these a search term and a topic).

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    Stage D2-C761 Day 2 · Google Trends

    The Google Trends Explore page, which Google called the heart of Trends, shows search interest in a query or topic and how it changes over time.

  10. Stage D3-C048 Day 3 · Making sense of users' queries

    Google generally treats spellings with and without diacritics as synonyms behind the scenes, for example a German 'ü' written as 'ü', as 'ue' or left out.

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    Stage D2-C600 Day 2 · Focusing on Internationalisation and Localisation

    Google usually understands a query word whether it is written with or without diacritics (accents).

  11. Stage D3-C059 Day 3 · Making sense of users' queries

    Google treats fan-out queries generated by the LLM the same way as queries typed by users, so understanding how normal queries work explains fan-out queries too.

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    Stage D1-C172 Day 1 · Welcome and opening keynotes

    Google said the Gemini model lets Search understand the user's intent, and query fan-out then adds further queries to the first one to enrich the quality of the answer.

  12. Stage D3-C059 Day 3 · Making sense of users' queries

    Google treats fan-out queries generated by the LLM the same way as queries typed by users, so understanding how normal queries work explains fan-out queries too.

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    Stage D2-C727 Day 2 · How does the index look like?

    Google said that when AI Overviews or AI Mode run a query fan-out, the generated queries are sent to Google's Search index and documents come back with their snippets, which then feed the AI-generated answer (part of this passage is unclear in the recording).

  13. Stage D3-C075 Day 3 · Making sense of users' queries

    At retrieval, Google splits the query into words, applies query understanding and expansion, and matches the words and their expansions against the posting lists.

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    Stage D2-C736 Day 2 · How does the index look like?

    In posting-list retrieval, the posting lists of the query's words are intersected, which yields an unranked list of candidate URLs.

  14. Stage D3-C075 Day 3 · Making sense of users' queries

    At retrieval, Google splits the query into words, applies query understanding and expansion, and matches the words and their expansions against the posting lists.

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    Stage D2-C738 Day 2 · How does the index look like?

    At retrieval, Google looks up the posting lists of the query words that are actually important rather than of every word in the query.

  15. Stage D3-C077 Day 3 · Making sense of users' queries

    The first condition for retrieving a document is that the query's words, or its concepts in the case of vectors or embeddings, are in the document or related to it.

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    Stage D2-C740 Day 2 · How does the index look like?

    Besides posting lists, Google can retrieve documents through vector embeddings: parts of documents are associated with embeddings, which form a vector space used for retrieval.

  16. Stage D3-C079 Day 3 · Making sense of users' queries

    To order candidates at retrieval, Google uses signals collected during indexing, and the first two are language and country.

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    Stage D2-C649 Day 2 · Calculating (some) signals

    Country and language are among Google's most important signals and have been used since Google's early days.

  17. Stage D3-C079 Day 3 · Making sense of users' queries

    To order candidates at retrieval, Google uses signals collected during indexing, and the first two are language and country.

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    Stage D2-C722 Day 2 · How does the index look like?

    Each document in Google's index has pretty much all the signals calculated for it attached, for example quality signals plus the page's country and language, according to an illustration the speaker called an approximation of the real structure.

  18. Stage D3-C080 Day 3 · Making sense of users' queries

    At retrieval, Google tries to match results to the user's language wherever possible: someone searching in Spanish does not necessarily want results in Italian.

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    Stage D2-C654 Day 2 · Calculating (some) signals

    In ranking, country and language signals help Google serve users the right content for their country and language.

  19. Stage D3-C082 Day 3 · Making sense of users' queries

    Country is the second retrieval signal: a user searching from Switzerland wants cheese from Switzerland, not from Germany, and a user in Spain is poorly served by results targeting a South American country.

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    Stage D2-C649 Day 2 · Calculating (some) signals

    Country and language are among Google's most important signals and have been used since Google's early days.

  20. Stage D3-C083 Day 3 · Making sense of users' queries

    Google called quality the most important of the signals used to order candidates at retrieval: a URL of high quality is more likely to be retrieved from the index for specific queries.

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    Stage D2-C722 Day 2 · How does the index look like?

    Each document in Google's index has pretty much all the signals calculated for it attached, for example quality signals plus the page's country and language, according to an illustration the speaker called an approximation of the real structure.

  21. Analysis D3-C135 Day 3 · How Google thinks about Quality

    The quality talk's slide listed MUM among Google's ranking systems, while Google's ranking systems guide says MUM is not currently used for general ranking in Search; read the slide as a list of systems Google runs, not as proof that each one ranks every query.

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    Docs D1-C130 Day 1 · How Search works and where's AI?

    Google's ranking systems guide says MUM is not currently used for general ranking in Search, only for specific applications such as COVID-19 vaccine searches and featured snippet callouts.

  22. Stage D3-C147 Day 3 · How Google thinks about Quality

    Google's quality talk said that at any moment thousands of Search experiments are probably running.

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    Stage D1-C158 Day 1 · Welcome and opening keynotes

    Google said that even the classic ten-blue-links layout was settled only after millions of experiments, as part of using as much data as possible for product decisions.

  23. Stage D3-C170 Day 3 · How Google thinks about Quality

    Google's quality talk pointed to page 21 of the Search Quality Rater Guidelines for its definition of content quality by effort, originality, talent or skill and accuracy, noting that the document is updated from time to time.

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    Stage D2-C311 Day 2 · Understanding what's on a page

    Gary Illyes pointed to Google's Search Quality Rater Guidelines as the detailed source on how Google thinks about the main content of a page.

  24. Stage D3-C212 Day 3 · How Google thinks about Quality

    Google's quality talk said Google clarified that traditional spam techniques aimed at manipulating AI responses also violate its spam policies, and that Google can take action against them.

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    Docs D1-C129 Day 1 · How Search works and where's AI?

    Google's guide says creating separate content for every variation of how people might search, including fan-out queries, primarily to manipulate rankings or AI responses violates its scaled content abuse policy. It adds that its AI systems can understand a page's relevance even without an exact match to the query.

  25. Slide D3-C224 Day 3 · Uncovering Trustworthy Experiences on Discover

    Google's Discover slide recommended large images at least 1,200 px wide, with more than 300,000 total pixels and a 16x9 aspect ratio, enabled by the max-image-preview:large setting.

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    Stage D2-C089 Day 2 · Controlling indexing

    max-image-preview:large matters mainly in Discover, where it allows a large image that draws people's attention, so the rule can make a page more visible than leaving it out, John Mueller said.

  26. Docs D3-C287 Day 3 · What are quality updates

    Google's spam updates page says its automated spam detection systems run constantly, and a notable improvement to them, such as to the AI-based SpamBrain system, is called a spam update and listed with Google's ranking updates.

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    Stage D2-C670 Day 2 · Calculating (some) signals

    SpamBrain is central to Google's spam-fighting efforts and has been improved many times since its launch.

  27. Stage D3-C311 Day 3 · How Search results are born

    Google handles an image used as a search query much like a text query interpreted as an embedding: the image is broken down into vectors (embeddings) that are then searched for in the index.

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    Stage D2-C740 Day 2 · How does the index look like?

    Besides posting lists, Google can retrieve documents through vector embeddings: parts of documents are associated with embeddings, which form a vector space used for retrieval.

  28. Stage D3-C316 Day 3 · How Search results are born

    Google generates the parts of a text result, such as title link and snippet, from its understanding of the underlying web page, even when the site owner provides nothing extra.

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    Stage D2-C724 Day 2 · How does the index look like?

    The snippet shown for a web result is reconstructed from the tokens stored in Google's index: Google knows the position of each token in the document and rebuilds the snippet from those positions.

  29. Stage D3-C317 Day 3 · How Search results are born

    Google can add elements to a text result, such as a 'highly cited' badge or a preferred-source badge.

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    Slide D1-C027 Day 1 · What's new in the world of Search

    Sites that users mark as a preferred source are more visible in Top Stories and are labelled in AI Mode and AI Overviews.

  30. Stage D3-C319 Day 3 · How Search results are born

    Image results shown among web results come from Google's image index and are roughly the same images that Google Images shows for the same query.

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    Stage D2-C525 Day 2 · Using images to your advantage and Engaging Search users with videos

    An image Google has extracted can appear almost anywhere Google shows results, including Discover, image search, web search and AI features, so its potential reach is immense.

  31. Stage D3-C323 Day 3 · How Search results are born

    Most of Google's search features need nothing extra from the site owner; Google generates them from what it extracted from the page during indexing.

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    Stage D2-C446 Day 2 · Finding the gold nuggets: structured data, media, and more!

    The 'gold nuggets' that Google's feature extraction step pulls out of a page's HTML are structured data (such as JSON-LD), images and videos.

  32. Stage D3-C324 Day 3 · How Search results are born

    Rich results differ from other search features because Google builds them from extra data that site owners provide, usually structured data and usually in JSON-LD format.

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    Stage D2-C521 Day 2 · What is Structured Data and why we need it on the internet.

    Structured data makes pages eligible to appear as rich results, Google's structured data talk said in its recap.

  33. Stage D3-C325 Day 3 · How Search results are born

    AI Mode and AI Overviews are not rich results but standard search features: they need no structured data to function and work with the normal text results from Google's index.

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    Stage D2-C726 Day 2 · How does the index look like?

    AI Overviews and AI Mode use the same index structures and token-based snippets as classic web results, a point Google called important but not obvious.

  34. Stage D3-C337 Day 3 · How Search results are born

    Review structured data lets a site specify how its users rated something; the review snippet shows an average star rating and often the number of reviews of a product, service or piece of content.

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    Stage D2-C454 Day 2 · What is Structured Data and why we need it on the internet.

    Structured data turns the loosely structured web into structured information that powers visual search features such as review stars and recipe filters (for example by preparation time).

  35. Stage D3-C341 Day 3 · How Search results are born

    Some countries rely a lot on social proof such as reviews, Google's speaker said, recalling a point from Google's Day 2 internationalisation talk.

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    Stage D2-C614 Day 2 · Focusing on Internationalisation and Localisation

    According to consumer data shown on a slide in the talk (source not captured), US consumers judge product quality more by user feedback and reviews, while European shoppers seem to look more at brand reputation.

  36. Stage D3-C647 Day 3 · How long does it take to..?

    Google may never use structured data from a site it does not trust: once it sees markup it does not trust, it does not touch it.

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    Stage D2-C500 Day 2 · What is Structured Data and why we need it on the internet.

    Structured data that is not relevant to the page's content can be treated as abusive: Google's filters make it ineffective, and egregious cases can lead to a manual action.

  37. Stage D3-C697 Day 3 · Wrapping all up: AI, Search, and making sense of everything.

    Google's Search Quality Rater Guidelines point out that the tool used to create content is not the problem, but how it was used and what for.

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    Docs D2-C611 Day 2 · Focusing on Internationalisation and Localisation

    Google's spam policies define scaled content abuse as generating many pages mainly to manipulate rankings, with little or no value to users, no matter how they are created, and list automated translating of scraped content among the examples.

  38. Stage D3-C056 Day 3 · Making sense of users' queries

    Google's generative AI features in Search build on the traditional ways of searching, so query understanding also flows into AI Overviews and AI Mode.

    repeats
    Slide D1-C051 Day 1 · How Search works and where's AI?

    Three reasons were given: generative AI features are built directly on the core ranking systems, query fan-out expands the original query to find related information, and generative AI features highlight content indexed by Google Search.

  39. Stage D3-C074 Day 3 · Making sense of users' queries

    Google's index uses posting lists: for each word, a list of the URLs associated with that word.

    repeats
    Stage D2-C733 Day 2 · How does the index look like?

    For most of the tokens Google finds on the web, though not every single one, the index keeps a posting list of the URLs that contain that token.

  40. Stage D3-C076 Day 3 · Making sense of users' queries

    For retrieval, Google uses signals attached individually to each document in the index.

    repeats
    Stage D2-C722 Day 2 · How does the index look like?

    Each document in Google's index has pretty much all the signals calculated for it attached, for example quality signals plus the page's country and language, according to an illustration the speaker called an approximation of the real structure.

  41. Slide D3-C224 Day 3 · Uncovering Trustworthy Experiences on Discover

    Google's Discover slide recommended large images at least 1,200 px wide, with more than 300,000 total pixels and a 16x9 aspect ratio, enabled by the max-image-preview:large setting.

    repeats
    Stage D2-C936 Day 2 · Using images to your advantage and Engaging Search users with videos

    Setting the max-image-preview robots meta tag to large can make content perform surprisingly well in Discover, Gary Illyes said.

  42. Stage D3-C311 Day 3 · How Search results are born

    Google handles an image used as a search query much like a text query interpreted as an embedding: the image is broken down into vectors (embeddings) that are then searched for in the index.

    repeats
    Stage D1-C224 Day 1 · How Search works and where's AI?

    For visual search, Google breaks an image down into vectors, sends the vectors to the index and returns results based on them.

  43. Stage D3-C329 Day 3 · How Search results are born

    Google's structured data feature guide lists the kinds of structured data Google supports with a search feature and what each can do to a site's search results.

    repeats
    Slide D2-C490 Day 2 · What is Structured Data and why we need it on the internet.

    Google recommends using the Search gallery in its developer documentation to find the structured data features that suit a site; the gallery shows each feature and how Google uses the markup.