Reference · originated
The AEO Index
Fifty questions about this beat — definitions, statistics, what is currently true, the cases, the tools — put to the answer engines through their APIs, built to run once a week. What comes back is who they cite. The panel is fixed, the method is below, and this wire's own count is on the table whatever it is, because a measurement of citation that omits the measurer is the kind of number this record exists to flag.
Week of Sep 21, 2026
Paused. This is the latest run; the weekly runs stopped after it because the engine API keys aren't in place. The panel and method are unchanged, and the next run will post here.
Engines marked web UI were run through the product's own interface in a logged-in browser rather than its API — one account, one run, personalisation on — because no API key was available. A different instrument; compare a web-UI week with an API week only with that in mind.
Perplexity (web UI, logged-in browser, one run)
50 answered · 50 with citations · this wire cited in 1
| Domain | Answers citing it |
|---|---|
| searchenginejournal.com | 21 |
| linkedin.com | 15 |
| developers.google.com | 12 |
| reddit.com | 12 |
| searchengineland.com | 12 |
| semrush.com | 9 |
| arxiv.org | 7 |
| blog.google | 6 |
| digitalapplied.com | 6 |
| otterly.ai | 6 |
| seroundtable.com | 6 |
| support.google.com | 6 |
| sqmagazine.co.uk | 6 |
| bing.com | 5 |
| en.wikipedia.org | 5 |
Google AI Mode (web UI, logged-in browser, one run)
50 answered · 50 with citations · this wire cited in 0
| Domain | Answers citing it |
|---|---|
| linkedin.com | 23 |
| reddit.com | 18 |
| youtube.com | 18 |
| searchenginejournal.com | 11 |
| semrush.com | 10 |
| searchengineland.com | 10 |
| digiday.com | 6 |
| digitalapplied.com | 5 |
| aisearch.similarweb.com | 4 |
| authoritytech.io | 4 |
| seroundtable.com | 4 |
| techcrunch.com | 4 |
| en.wikipedia.org | 3 |
| omnibound.ai | 3 |
| promptwatch.com | 3 |
By question
| Question | Type | perplexity-web | google-ai-mode-web |
|---|---|---|---|
| What is answer engine optimization (AEO)? | definition | ahrefs.com, airops.com, austinheaton.com, bing.com +8 | contently.com, coursera.org, hubspot.com, jasper.ai +7 |
| What is the difference between AEO and GEO? | definition | aol.com, arxiv.org, business.adobe.com, developers.google.com +10 | business.adobe.com, jasper.ai, linkedin.com, muckrack.com +3 |
| What is generative engine optimization? | definition | aol.com, arxiv.org, blog.google, developers.google.com +8 | en.wikipedia.org, manhattanstrategies.com, moz.com, salesforce.com +2 |
| What is an answer engine? | definition | cacm.acm.org, conductor.com, councils.forbes.com, hubspot.com +6 | 1digitalagency.com, 5wpr.com, cacm.acm.org, fastcompany.com +8 |
| What is citation share in AI search? | definition | aisearch.similarweb.com, arxiv.org, authoritytech.io, cintra.run +11 | 1digitalagency.com, aisearch.similarweb.com, anthropic.com, authoritytech.io +8 |
| What is citation decay? | definition | arxiv.org, casrai.org, demand-genius.com, digitalapplied.com +10 | 5wpr.com, astiva.ai, linkedin.com, machinerelations.ai +6 |
| How stable are the sources AI engines cite week to week? | definition | abhs.in, gemini.google.com, m.thewire.in, markets.businessinsider.com +9 | brightedge.com, getmentions.ai, linkedin.com, mintec.co +4 |
| What is query fan-out in AI search? | definition | 85sixty.com, ahrefs.com, aisearch.similarweb.com, an-digital.com +11 | ahrefs.com, aisearch.similarweb.com, digiday.com, linkedin.com +4 |
| What is grounding in generative AI search? | definition | agicent.com, ai.google.dev, colab.research.google.com, decagon.ai +9 | cloro.dev, dawiso.com, decagon.ai, salesforce.com +1 |
| What is AI visibility and how is it measured? | definition | analyticahouse.com, arxiv.org, bigeyeagency.com, finance.yahoo.com +11 | builtin.com, digiday.com, duda.co, frase.io +5 |
| What is a zero-click search? | definition | articsledge.com, en.wikipedia.org, forbes.com, neilpatel.com +6 | bain.com, bemarketing.com, digitalapplied.com, en.wikipedia.org +6 |
| What is llms.txt and does Google use it? | definition | ahrefs.com, baselinelabs.ai, contentful.com, developer.chrome.com +9 | ai-visibility.org.uk, developer.chrome.com, llmtxt.info, medium.com +5 |
| Which AI crawlers should a website allow or block, and what does each one do? | definition | blogs.bing.com, chrisleverseo.com, crawlercheck.com, developers.cloudflare.com +11 | buzzstream.com, clickrank.ai, cloudflare.com, geotoolbox.ai +5 |
| What is Google Coati? | definition | anythingengineoptimization.com, colab.research.google.com, diztinct.com, en.wikipedia.org +9 ★ | facebook.com, gtechme.com, loganix.com, mightywarner.ae +2 |
| What is Google Discover and why does it matter to publishers? | definition | almcorp.com, cutinside.com, developers.google.com, launchcodex.com +11 | blog.google, cxfusion.io, izooto.com, linkedin.com +5 |
| What is the AI Performance report in Bing Webmaster Tools? | definition | bing.com, blog.devgenius.io, blogs.bing.com, experienceleague.adobe.com +4 | about.ads.microsoft.com, bing.com, blogs.bing.com, experienceleague.adobe.com +2 |
| What is Google AI Mode? | definition | blog.google, desmoinesregister.com, natlawreview.com, one.google.com +6 | blog.google, en.wikipedia.org, evertune.ai, facebook.com +5 |
| What is agentic search? | definition | actian.com, brave.com, conductor.com, cube.dev +5 | actian.com, decagon.ai, docs.opensearch.org, entlify.com +4 |
| What percentage of Google searches show an AI Overview? | statistic | 9to5google.com, bastillepost.com, conbersa.ai, digiday.com +10 | heroicrankings.com, omnibound.ai, searchengineland.com, seroundtable.com +3 |
| What is the market share of AI search compared with Google? | statistic | aisearch.similarweb.com, apnews.com, beanstalkim.com, biz.chosun.com +8 | aisearch.similarweb.com, digitalapplied.com, getpassionfruit.com, gs.statcounter.com +11 |
| What share of Google searches end without a click to the open web? | statistic | aisearch.similarweb.com, cicero.studio, click-vision.com, dailysabah.com +10 | aisearch.similarweb.com, arcalea.com, click-vision.com, forbes.com +5 |
| How many people use ChatGPT for search and do they still use Google? | statistic | biz.chosun.com, cryptobriefing.com, economictimes.indiatimes.com, firstpagesage.com +10 | adobe.com, firstpagesage.com, linkedin.com, reddit.com +4 |
| Which websites are cited most in Google AI Overviews? | statistic | aeovision.ai, ahrefs.com, everything-pr.com, omnibound.ai +7 | ahrefs.com, cxl.com, digitalapplied.com, promptwatch.com +3 |
| Are Reddit citations in AI answers rising or falling? | statistic | brightedge.com, cmswire.com, cognizo.ai, discoveredlabs.com +10 | brightedge.com, linkedin.com, mashable.com, nowoka.com +5 |
| How much is Google AI Mode actually used? | statistic | biz.chosun.com, blog.google, cmswire.com, gpt-insights.de +8 | aeovision.ai, aibusinessweekly.net, blog.google, getpanto.ai +7 |
| How much traffic are publishers losing to AI Overviews? | statistic | dailysabah.com, digiday.com, highervisibility.com, issuewire.com +9 | digiday.com, emarketer.com, linkedin.com, pressgazette.co.uk +2 |
| How much of publishers' Google traffic comes from Discover versus Search? | statistic | developers.google.com, digiday.com, evolvedash.com, linkedin.com +8 | digiday.com, linkedin.com, pressgazette.co.uk, raptive.com +1 |
| How many times do AI crawlers fetch a site for each visit AI search sends back? | statistic | blog.adyog.com, blog.cloudflare.com, community.mojeek.com, digiday.com +10 | besourceable.com, blog.cloudflare.com, digitalapplied.com, linkedin.com +2 |
| How often do AI engines use a source without naming the brand? | statistic | adriel.com, arxiv.org, citate.ai, cxl.com +11 | authoritytech.io, dev.to, linkedin.com, semrush.com +2 |
| How big is ChatGPT's advertising business? | statistic | ads.openai.com, cnbc.com, finance.yahoo.com, help.openai.com +6 | cnbc.com, forbes.com, inc.com, linkedin.com +2 |
| If I block AI training crawlers, do I lose visibility in AI search? | state | amicited.com, anagram.ai, developers.google.com, developers.openai.com +8 | blog.cloudflare.com, competlab.com, emotedigital.com.au, nytroseo.com +3 |
| Why do AI visibility tools give different citation numbers for the same brand? | state | ai.joaoqueiros.com, birdeye.com, campaigncreators.com, einpresswire.com +9 | authoritytech.io, blumint.co, buzzstream.com, dev.to +6 |
| What controls do publishers have over appearing in AI Overviews? | state | almcorp.com, blog.google, developers.google.com, digitalapplied.com +8 | clearscope.io, digiday.com, digitalinformationworld.com, heybuffy.com +9 |
| What on-page changes actually increase AI citations? | state | arxiv.org, bing.com, developers.google.com, dl.acm.org +9 | ahrefs.com, discoveredlabs.com, heybuffy.com, linkedin.com +4 |
| Can a brand pay to appear in AI answers? | state | accordtechsolutions.com, bir.ch, blog.google, help.openai.com +8 | adage.com, digitalapplied.com, franco.com, independent.co.uk +5 |
| Will the courts stop AI engines from using publishers' content? | state | ailawsuittracker.com, axis-intelligence.com, bakerlaw.com, clearyiptechinsights.com +10 | builtin.com, digiday.com, eff.org, lawcommentary.com +5 |
| Is being cited by an AI engine the same as being recommended by it? | state | atlasworkspace.ai, bluearcher.com, cheers.tech, cxl.com +9 | authoritytech.io, buttondown.com, desmoinesregister.com, linkedin.com +4 |
| What is the status of the Bartz v. Anthropic settlement and when are authors paid? | news | andibartz.substack.com, anthropiccopyrightsettlement.com, authorsalliance.org, authorsguild.org +8 | anthropiccopyrightsettlement.com, authorsguild.org, societyofauthors.org, taaonline.net +1 |
| What is happening in the Databricks Mosaic LLM copyright case? | news | app.midpage.ai, cfmlawyers.ca, chatgptiseatingtheworld.com, innercitypress.com +9 | chatgptiseatingtheworld.com, innercitypress.com, lunch.publishersmarketplace.com, mealeys.com +3 |
| What happened in Google's DMCA case against SerpApi? | news | almcorp.com, builtplain.com, caselaw.findlaw.com, chatgptiseatingtheworld.com +13 | caselaw.findlaw.com, chatgptiseatingtheworld.com, linkedin.com, morningstar.com +4 |
| What is the status of Reddit's lawsuit against Perplexity and SerpApi? | news | chatgptiseatingtheworld.com, courtlistener.com, law.com, mealeys.com +7 | arstechnica.com, courtlistener.com, jdsupra.com, law.com +4 |
| What did the UK CMA order Google to do about AI Overviews and publishers? | news | britannica.com, cityam.com, en.wikipedia.org, globalbankingandfinance.com +4 | apnews.com, arstechnica.com, gov.uk, siliconangle.com +3 |
| What did Cloudflare change about AI crawler defaults on September 15, 2026? | news | blog.cloudflare.com, cloudflare.com, developers.cloudflare.com, gulfnews.com +6 | blog.cloudflare.com, cloudflare.com, developers.cloudflare.com, helpnetsecurity.com +5 |
| What position did the US Justice Department take on AI training and fair use? | news | abovethelaw.com, copyright.gov, jdsupra.com, linkedin.com +6 | linkedin.com, local21news.com, lowenstein.com, michaelparekh.substack.com +3 |
| Has the EU designated ChatGPT a very large online search engine? | news | biz.chosun.com, caliber.az, cybersecuritynews.com, devdiscourse.com +8 | azoma.ai, digital-strategy.ec.europa.eu, gizmodo.com, instagram.com +2 |
| Which tools track how often a brand is cited in ChatGPT and Perplexity? | tool | 01net.com, adgully.com, alignify.co, analyticsinsight.net +13 | fpgrowth.io, jetfuel.agency, nicklafferty.com, otterly.ai +5 |
| Does Google Search Console report performance in AI Overviews? | tool | abmagency.com, cmswire.com, cogny.com, crawlraven.com +8 | linkedin.com, neilpatel.com, quora.com, reddit.com +2 |
| Which search engine gives first-party citation data to site owners? | tool | apwebsolutions.com.au, bing.com, blogs.bing.com, cxl.com +5 | jaxonparrott.com, launchcodex.com, searchenginejournal.com, searchenginewatch.com |
| What are the current best practices for answer engine optimization? | practice | bing.com, blogs.bing.com, demandsphere.com, developers.google.com +8 | fptsoftware.com, linkedin.com, position.digital, reddit.com +2 |
| Where can I follow AI-search industry news? | practice | 9to5google.com, blog.google, developers.google.com, openai.com +4 | artificialintelligence-news.com, position.digital, reddit.com, searchenginejournal.com +4 |
Earlier weeks
- Sep 7, 2026 — perplexity-web: wire cited in 5 · google-ai-mode-web: wire cited in 0 · openai-web: wire cited in 0
The panel
50 questions, version 2026-09-12, fixed: a measurement that changes its sample cannot show change. They come from the demand the record can see — Search Console queries, the State of Search's own questions, the docket's cases — not from what the wire would like to be asked. Types: definition, statistic, state, news, tool, practice.
Every question
- What is answer engine optimization (AEO)? (definition)
- What is the difference between AEO and GEO? (definition)
- What is generative engine optimization? (definition)
- What is an answer engine? (definition)
- What is citation share in AI search? (definition)
- What is citation decay? (definition)
- How stable are the sources AI engines cite week to week? (definition)
- What is query fan-out in AI search? (definition)
- What is grounding in generative AI search? (definition)
- What is AI visibility and how is it measured? (definition)
- What is a zero-click search? (definition)
- What is llms.txt and does Google use it? (definition)
- Which AI crawlers should a website allow or block, and what does each one do? (definition)
- What is Google Coati? (definition)
- What is Google Discover and why does it matter to publishers? (definition)
- What is the AI Performance report in Bing Webmaster Tools? (definition)
- What is Google AI Mode? (definition)
- What is agentic search? (definition)
- What percentage of Google searches show an AI Overview? (statistic)
- What is the market share of AI search compared with Google? (statistic)
- What share of Google searches end without a click to the open web? (statistic)
- How many people use ChatGPT for search and do they still use Google? (statistic)
- Which websites are cited most in Google AI Overviews? (statistic)
- Are Reddit citations in AI answers rising or falling? (statistic)
- How much is Google AI Mode actually used? (statistic)
- How much traffic are publishers losing to AI Overviews? (statistic)
- How much of publishers' Google traffic comes from Discover versus Search? (statistic)
- How many times do AI crawlers fetch a site for each visit AI search sends back? (statistic)
- How often do AI engines use a source without naming the brand? (statistic)
- How big is ChatGPT's advertising business? (statistic)
- If I block AI training crawlers, do I lose visibility in AI search? (state)
- Why do AI visibility tools give different citation numbers for the same brand? (state)
- What controls do publishers have over appearing in AI Overviews? (state)
- What on-page changes actually increase AI citations? (state)
- Can a brand pay to appear in AI answers? (state)
- Will the courts stop AI engines from using publishers' content? (state)
- Is being cited by an AI engine the same as being recommended by it? (state)
- What is the status of the Bartz v. Anthropic settlement and when are authors paid? (news)
- What is happening in the Databricks Mosaic LLM copyright case? (news)
- What happened in Google's DMCA case against SerpApi? (news)
- What is the status of Reddit's lawsuit against Perplexity and SerpApi? (news)
- What did the UK CMA order Google to do about AI Overviews and publishers? (news)
- What did Cloudflare change about AI crawler defaults on September 15, 2026? (news)
- What position did the US Justice Department take on AI training and fair use? (news)
- Has the EU designated ChatGPT a very large online search engine? (news)
- Which tools track how often a brand is cited in ChatGPT and Perplexity? (tool)
- Does Google Search Console report performance in AI Overviews? (tool)
- Which search engine gives first-party citation data to site owners? (tool)
- What are the current best practices for answer engine optimization? (practice)
- Where can I follow AI-search industry news? (practice)
Method, and what this is not
- One run per question per engine per week, default parameters, no system prompt beyond the question, no retries on content. The engines are non-deterministic; a week is one sample, not a ranking.
- "Cited" means a URL the engine returned as a citation for that answer. Domains are counted once per answer. Being cited is not being recommended — see the State of Search.
- Google AI Overviews and AI Mode have no API. AI Mode can be run through its web interface in a browser (
udm=50) and is recorded that way, labelled web UI; AI Overviews are not measured. Gemini with Search grounding is a different product and is labelled as itself. - This wire is a subject of its own measurement. Its count is reported on the same terms as every other domain's, and the panel was written before the first run.
- Engine models are pinned per run and recorded; when one changes, the week says so.
The data on this page is free to reuse under CC BY 4.0, credited to AEO Wire.
Last Week in AI Search
The week's record, Monday 7am ET: what shipped, who got cited, where the law and money moved. Dated, sourced, no takes. Read a past issue first if you like.