The numbers, newest first

What changed in ChatGPT, Google AI Mode and AI Overviews, Perplexity, Gemini, Claude and Copilot, and what it means for the people responsible for being found.

Briefs and data

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  1. BriefCrawlers

    Google and Microsoft back a shared AI training opt-out in robots.txt

    Google and Microsoft plan to read one AI training opt-out in robots.txt in 2027, and at Google the same line also takes a site out of Gemini Apps grounding.

  2. BriefGoogle

    Google spam guidance now covers shareable pages and generated outputs

    Google spam guidance now tells services with shareable pages, generated outputs or tools to noindex link-only pages, and only indexed pages reach AI Overviews.

  3. BriefMeasurement

    Growth Memo data puts AI referral traffic at 0.5% of total visits

    AI referral traffic grew 5.6x in the US in two years and is still 0.5% of visits, so the recommendation inside the answer is what brands should track.

  4. DataResearch

    How much AI search visibility European brands have in 2026

    AI search visibility for the median European brand is 5% of answers about its category, and 72% of 90 brands stay below 15% in their category.

  5. BriefChatGPT

    OpenAI's GPT-6 rollout hides a week of ChatGPT referral traffic

    ChatGPT referral traffic was counted as Direct from 8 to 16 October 2026, so GA4 reports for those days undercount ChatGPT and need a note.

  6. BriefGoogle

    Opt-out test puts Google AI Overviews and AI Mode CTR at about 0.9%

    An opt-out test put AI Overviews and AI Mode CTR at about 0.9% for one site, and Google gives no separate AI click data, so brands measure value themselves.

  7. BriefClaude

    Peec AI finds Claude search uses Brave and reads an eighth of a page

    Peec AI found Claude search draws on Brave and passes about an eighth of a page to its model, so the answer passage has to sit near the top.

  8. BriefChatGPT

    Peec AI researcher finds ChatGPT kept citing a fake statistics site

    ChatGPT kept fetching a Peec AI researcher's site of fake statistics after Google dropped it, so brands that publish sourced numbers of their own gain.

  9. BriefResearch

    University of Toronto study finds retrieval drives AI citations

    A University of Toronto study of what drives AI citations found search retrieval outweighs page features, so pages have to match how the model searches.

  10. DataResearch

    Which websites ChatGPT, Google AI Overviews and Perplexity cite most

    The websites ChatGPT, Google AI Overviews and Perplexity cite most differ by engine, and for one brand the three share a median 2 of their top 10.

  11. BriefResearch

    Ahrefs study of AI citation stability finds half gone the next day

    Ahrefs measured AI citation stability for 20 days and found half or more of citations gone the next day, so a single check misreads a brand's AI visibility.

  12. BriefGoogle

    Google launches Universal Cart across Search and the Gemini app

    Universal Cart lets U.S. shoppers save and buy products from many stores in Google Search and Gemini, so retailers missing from AI answers lose the sale.

Data

How much AI search visibility European brands have in 2026

AI search visibility for the median European brand is 5% of answers about its category, and 72% of 90 brands stay below 15% in their category.

The median brand appears in 5.0% of AI answers about its category, and the 90th percentile brand reaches 29.6%.
Figure 1. The median brand appears in 5.0% of AI answers about its category, and the 90th percentile brand reaches 29.6%.

Data

Which websites ChatGPT, Google AI Overviews and Perplexity cite most

The websites ChatGPT, Google AI Overviews and Perplexity cite most differ by engine, and for one brand the three share a median 2 of their top 10.

ChatGPT, Google AI Overviews and Perplexity share a median 2 of their top 10 cited websites; any two share 3 or 4.
Figure 1. ChatGPT, Google AI Overviews and Perplexity share a median 2 of their top 10 cited websites; any two share 3 or 4.

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The week in AI search, in one email

One email a week with what changed in ChatGPT, Google AI Mode, Perplexity and Gemini, and the week's data piece.