Research · October 2026

Where Does AI Get Its Information? Five Engines Compared

Where does AI get its information depends on the engine. We measured the sites each one cites for the same 250 buyer questions across 25 sectors.

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Short answer

Where does AI get its information?

AI engines combine training data with live web search, and each engine cites very different sites. In LLMReach's measurement, Google AI Overviews cited Reddit in 25.4% of answers, while ChatGPT, Gemini and Perplexity together cited it in 1.5%.

Key figures

Where AI engines get their information, in numbers

of Google AI Overviews cited Reddit
25.4%
of Google AI Overviews cited Reddit
LLMReach measurement, October 2026
of Google AI Overviews cited YouTube
27.8%
of Google AI Overviews cited YouTube
LLMReach measurement, October 2026
of ChatGPT, Gemini and Perplexity answers cited Reddit (Google AI Overviews: 25.4%)
1.5%
of ChatGPT, Gemini and Perplexity answers cited Reddit (Google AI Overviews: 25.4%)
LLMReach measurement, October 2026
of the websites AI Overviews cite rank in Google's top 10 for the same search
44.3%
of the websites AI Overviews cite rank in Google's top 10 for the same search
LLMReach measurement, October 2026
of the websites ChatGPT cites rank in Google's top 10 (Perplexity 14.4%, Gemini 13.4%)
10.7%
of the websites ChatGPT cites rank in Google's top 10 (Perplexity 14.4%, Gemini 13.4%)
LLMReach measurement, October 2026
of Google AI Mode answers cited a Google-owned site (Google, Maps or YouTube)
36.3%
of Google AI Mode answers cited a Google-owned site (Google, Maps or YouTube)
LLMReach measurement, October 2026
websites cited per Perplexity answer, the most of the five engines
8.0
websites cited per Perplexity answer, the most of the five engines
LLMReach measurement, October 2026
different websites cited across the five engines, counted per engine
3,790
different websites cited across the five engines, counted per engine
LLMReach measurement, October 2026

Our data

Sites cited by each AI engine

Each engine on the same 250 buyer questions. Google AI Overviews appeared on 169 of them.
EngineAnswersSites per answerIn Google top 10Cite RedditMost cited site
ChatGPT2504.210.7%1.6%tripadvisor.com
Gemini2502.513.4%1.2%maps.google.com
Perplexity250814.4%1.6%expertise.com
Google AI Overviews1695.944.3%25.4%youtube.com
Google AI Mode2452.523.8%13.1%google.com

Source: LLMReach measurement, October 2026

What it means

What this means for your brand

  • Optimize engine by engine

    Each engine cites different sites. A single content plan will not cover ChatGPT, Gemini, Perplexity and Google AI equally.

  • Google rank only helps Google AI

    AI Overviews lean on top 10 pages far more than ChatGPT does, so classic SEO pays off mostly there.

  • Earn off-site mentions

    Perplexity cites eight sites per answer. Being present on third-party sources widens your chances of citation.

By engine

Share of answers citing each site

Per engine, % of answers or cited sites

  • ChatGPT
  • Gemini
  • Perplexity
  • Google AI Overviews
  • Google AI Mode
Source: LLMReach measurement, October 2026, 250 buyer questions in 25 sectorsView as table
Per engine, % of answers or cited sites
BrandChatGPTGeminiPerplexityGoogle AI OverviewsGoogle AI Mode
Sources in Google top 1010.7%13.4%14.4%44.3%23.8%
Answers citing Reddit1.6%1.2%1.6%25.4%13.1%
Answers citing YouTube0%0.4%0%27.8%7.8%

Our data

How each engine finds its sources

Most cited
  1. 01
    google.com
    https://cloud.google.com/bigquery/pricing
    cited in 138 of 1164 answers
    • ChatGPT
    • Gemini
    • Google AI Overviews
    • Google AI Mode
  2. 02
    reddit.com
    July 2026 broker deals ranked by TRUE effective monthly (payment + DAS + broker fee) — the 1% rule, actually computed
    cited in 86 of 1164 answers
    • ChatGPT
    • Gemini
    • Perplexity
    • Google AI Overviews
    • Google AI Mode
  3. 03
    youtube.com
    Best Payroll Systems for Hourly Teams - YouTube
    cited in 67 of 1164 answers
    • Gemini
    • Google AI Overviews
    • Google AI Mode
Also cited
  1. 04
    maps.google.com
    https://maps.google.com/?cid=17809755708024308314&g_mp=Cidnb29nbGUubWFwcy5wbGFjZXMudjEuUGxhY2VzLlNlYXJjaFRleHQ
    cited in 52 of 1164 answers
    • Gemini
  2. 05
    forbes.com
    Best Online Prescription Glasses 2026 | Tested - Forbes Vetted
    cited in 47 of 1164 answers
    • ChatGPT
    • Gemini
    • Perplexity
    • Google AI Overviews
    • Google AI Mode
  3. 06
    expertise.com
    13 Best Dallas, TX Tax Services | Expertise.com
    cited in 35 of 1164 answers
    • ChatGPT
    • Perplexity
  4. 07=
    g2.com
    Best Enterprise Data Security Posture Management (DSPM) in 2026 | G2
    cited in 31 of 1164 answers
    • ChatGPT
    • Gemini
    • Perplexity
    • Google AI Overviews
    • Google AI Mode
  5. 07=
    yelp.com
    John Eagle Honda Of Dallas - Dallas, TX
    cited in 31 of 1164 answers
    • Perplexity
    • Google AI Overviews
    • Google AI Mode
  6. 09
    tripadvisor.com
    THE 10 BEST Seafood Restaurants in Jacksonville (Updated 2026)
    cited in 30 of 1164 answers
    • ChatGPT
    • Perplexity
    • Google AI Overviews
    • Google AI Mode
  7. 10
    facebook.com
    Top Chicago News Sources - Facebook
    cited in 28 of 1164 answers
    • Gemini
    • Google AI Overviews
    • Google AI Mode
  8. 11
    linkedin.com
    Frank West | LinkedIn
    cited in 23 of 1164 answers
    • Perplexity
    • Google AI Overviews
    • Google AI Mode
  9. 12
    clutch.co
    Top PPC Agencies in Phoenix - Oct 2026 Rankings | Clutch.co
    cited in 22 of 1164 answers
    • ChatGPT
    • Gemini
    • Perplexity
    • Google AI Overviews

LLMReach measurement, 1164 answers, October 2026. Each site counted once per answer.

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How each engine finds its sources
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<a href="https://www.llmreach.ai/research/where-does-ai-get-its-information">
  <img src="https://www.llmreach.ai/charts/research/where-does-ai-get-its-information.svg" alt="How each engine finds its sources" width="800" loading="lazy" />
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<p>Source: <a href="https://www.llmreach.ai/research/where-does-ai-get-its-information">Where AI gets its information by LLMReach</a></p>

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Methodology

How we measured where AI gets its information

Assistants measured
ChatGPTgpt-5-6250
Gemini3.5 Flash-Lite250
Perplexitysonar250
Google AI OverviewsGoogle Search, US desktop250
Google AI ModeGoogle AI Mode, US desktop250
10 example buyer questions, from the 250 asked to each assistant
  1. 01best digital marketing agency in Chicago for B2B companies
  2. 02best HR and payroll platform for a US company with 50 employees
  3. 03who is the best family dentist in Houston that takes new patients?
  4. 04best online degree for an accounting career
  5. 05best pizza in Chicago
  6. 06best pest control company in Jacksonville for termites
  7. 07best car insurance for young drivers in Houston
  8. 08best dry cleaner in Philadelphia for a wedding dress
  9. 09what are the most reliable news sources for US politics?
  10. 10best realtor in Phoenix for buying a rental property
  • We asked 250 buyer questions across 25 sectors to five engines: ChatGPT, Gemini, Perplexity, Google AI Overviews and Google AI Mode.
  • ChatGPT, Gemini and Perplexity were queried on 5 to 7 October 2026. Google AI Overviews and AI Mode were queried on 11 October 2026.
  • Each website is counted once per answer, and subdomains are grouped under their main domain. Totals are counted per engine.
  • Third-party facts come from primary sources such as OpenAI, Google and Perplexity documentation, and are linked next to each figure.

Cite this page

Cite this research

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<p>
  Source: <a href="https://www.llmreach.ai/research/where-does-ai-get-its-information">Where Does AI Get Its Information? Five Engines Compared</a>,
  LLMReach, updated October 2026.
</p>

Writers may quote these figures with a link to this page.

FAQ

Questions about where AI gets its information

Where does AI get its information?

AI engines draw on training data and, for many answers, live web search. OpenAI says ChatGPT's models use public web data, third-party partners, and user and trainer data. LLMReach's October 2026 measurement shows engines then cite very different sites.

Where does ChatGPT get its information?

According to the OpenAI Help Center, its models are developed from three primary sources: publicly available internet information, data from third-party partners, and user and trainer data. LLMReach found only 10.7% of the sites ChatGPT cites rank in Google's top 10.

What are Gemini sources and Gemini citations?

Google AI for Developers says Gemini can ground answers in real-time Google Search results and cite verifiable sources. LLMReach measured 13.4% of the websites Gemini cites ranking in Google's top 10 for the same search.

What are Perplexity sources and Perplexity citations?

The Perplexity Help Center says it searches the internet in real time and adds numbered citations to every answer. LLMReach measured 8.0 websites cited per Perplexity answer in October 2026, the most of the five engines.

What are the most cited domains in AI Overviews?

In LLMReach's October 2026 measurement, YouTube appeared in 27.8% of Google AI Overviews and Reddit in 25.4%. Pew Research Center, July 2025, found Wikipedia, YouTube and Reddit together made up 15% of sources in Google AI summaries.

How did LLMReach measure AI Overview citations?

LLMReach ran the same 250 buyer questions across 25 sectors through five engines in October 2026. It counted each website once per answer and grouped subdomains. 44.3% of the websites AI Overviews cite ranked in Google's top 10.

Keep exploring

Keep exploring the data

Free AI Audit

See which sites AI cites for you

You leave knowing where the gap is, what is causing it, and which changes would matter first, whether we work together or not.

What to expect

  1. Audit

    Before the call, we run your buyers' questions through ChatGPT, Claude, Perplexity and Gemini.

  2. Map

    On the call, we show you where competitors are cited and you are not, and what's causing it.

  3. Decide

    An honest read on whether the Citation Stack fits. If it doesn't, you'll hear it on the call.

Don't see a time that works? Email Karim directly: contact@llmreach.ai