YouTube is the most-cited website in AI answers, and almost all of that comes from Google: Google AI Overviews cites YouTube 6,894 times, while ChatGPT cites it 5 times on the same 2,984 questions. Across ChatGPT, Gemini, Perplexity and Google's AI features, YouTube appears in 20.1% of all answers, ahead of Reddit and Wikipedia.
Analysis of 155,312 citations · answers from ChatGPT, Gemini, Perplexity and Google's AI features, September 2026
Key Findings
- 1.Google AI Overviews cites YouTube 6,894 times, while ChatGPT cites it 5 times in answers to the same 2,984 questions.
- 2.YouTube is cited in 20.1% of AI answers, one in five, well ahead of Reddit (11.8%) and Wikipedia (11.1%).
- 3.The 20 most-cited websites receive 26.2% of all citations in AI answers, and the top 100 receive 43.9%.
- 4.ChatGPT's most-cited website is the National Institutes of Health's nih.gov, with 954 citations, followed by consumerfinance.gov (866) and irs.gov (426).
- 5.6 of the 20 most-cited websites in AI answers are government or health sources, led by nih.gov in 4th place with 2,126 citations.
Summary
Put the same question to ChatGPT and to Google and you get two different reading lists. Google's AI Overview tends to show a YouTube video and a Reddit thread, while ChatGPT points to the National Institutes of Health or the Consumer Financial Protection Bureau. Add up thousands of answers and a clear leaderboard of the websites AI engines rely on appears.
A citation is the source link an AI answer shows next to its claims, and it is how an AI answer sends a reader to a website. The leaderboard shows which sites AI engines trust enough to quote, and so where a business needs to be present, either with its own pages or by being discussed on the sites that already win.
YouTube tops the list by a wide margin: 12,857 citations and a place in 20.1% of all answers. Wikipedia (3,531 citations) and Reddit (3,471) follow, then the National Institutes of Health and Facebook. Behind that pooled ranking, every engine has its own favorite: Google AI Overviews cites YouTube 6,894 times, ChatGPT 5 times.
What we measured
In September 2026 we asked 2,984 general questions across 31 topics to ChatGPT, Gemini, Perplexity and Google AI Mode, and collected the Google AI Overview (the AI summary above Google's search results) for the same questions. We recorded every web page cited in the answers, 155,312 citations in all, grouped them by website and ranked the websites by total citations, overall and for each engine.
A citation is one source link in one answer; a page linked twice in the same answer counts once. A website is everything under one address, so all of Wikipedia's language versions count as wikipedia.org. Share of answers is the percentage of answers that cite a website at least once, which shows how often a reader sees it, whatever the number of links.
YouTube appears in one in five AI answers
YouTube's 12,857 citations are more than three times Wikipedia's 3,531. Almost all of them come from Google's two AI features: 6,894 from AI Overviews and 5,162 from AI Mode. Google's AI features cite video far more than any other engine does; YouTube is also owned by Google.
Source: Suff Digital analysis of 155,312 citations · answers from ChatGPT, Gemini, Perplexity and Google's AI features, September 2026
Reddit reaches more answers than Wikipedia, 11.8% against 11.1%, even though Wikipedia has slightly more citations. Reddit tends to appear once in many different answers, while Wikipedia more often has several of its pages cited in the same answer. For a reader, that makes Reddit the second most visible website in AI answers.
Each AI engine has a different favorite website
The pooled ranking hides five very different lists. Google AI Overviews and Google AI Mode are both led by YouTube, followed by Reddit and Wikipedia. Gemini's top source is Reddit, with 273 citations. Perplexity's is Wikipedia, with 979, and it also leans on Yahoo (752) and Microsoft (681). ChatGPT's is nih.gov, with 954.
Source: Suff Digital analysis of 155,312 citations · answers from ChatGPT, Gemini, Perplexity and Google's AI features, September 2026
| Engine | Most-cited website | Citations from that engine |
|---|---|---|
| Google AI Overviews | youtube.com | 6,894 |
| Google AI Mode | youtube.com | 5,162 |
| Perplexity | wikipedia.org | 979 |
| ChatGPT | nih.gov | 954 |
| Gemini | reddit.com | 273 |
The contrasts are sharp. ChatGPT cites YouTube 5 times and Facebook once, while Google AI Overviews cites them 6,894 and 938 times. Investopedia gets 584 citations from Perplexity and 5 from ChatGPT. The site that wins on one engine can be almost invisible on another, so a business needs to know which engines its customers use before deciding where to show up.
| Website | ChatGPT | Gemini | AI Mode | AI Overviews | Perplexity |
|---|---|---|---|---|---|
| youtube.com | 5 | 80 | 5,162 | 6,894 | 716 |
| wikipedia.org | 178 | 248 | 985 | 1,141 | 979 |
| reddit.com | 11 | 273 | 1,300 | 1,306 | 581 |
| nih.gov | 954 | 23 | 236 | 273 | 640 |
| facebook.com | 1 | 18 | 742 | 938 | 22 |
| microsoft.com | 419 | 53 | 244 | 323 | 681 |
| google.com | 127 | 185 | 890 | 283 | 151 |
| yahoo.com | 14 | 0 | 249 | 212 | 752 |
| consumerfinance.gov | 866 | 8 | 61 | 91 | 196 |
| irs.gov | 426 | 68 | 251 | 146 | 323 |
Government and health sites hold six of the top 20 places
Official and medical sources do well in AI answers. The National Institutes of Health is 4th overall with 2,126 citations, the Consumer Financial Protection Bureau's consumerfinance.gov 9th with 1,222 and the IRS 10th with 1,214. Health publishers Healthline (1,139), Cleveland Clinic (1,085) and Mayo Clinic (808) also make the top 20.
ChatGPT drives much of this. It cites consumerfinance.gov 866 times and irs.gov 426 times, more than any other engine, and nih.gov is its single most-cited website. When a question touches money or health, ChatGPT reaches for the official source first, so a business in those fields competes with government guidance on ChatGPT and with video and forums on Google.
A quarter of AI citations go to 20 websites
The 100 most-cited websites take 43.9% of all citations, and YouTube alone takes 8.3%. The rest is a long tail: 14,616 different websites were cited at least once, and 35.9% of them exactly once. A specific, useful page on a narrow question can still earn a citation without being a household name.
Source: Suff Digital analysis of 155,312 citations · answers from ChatGPT, Gemini, Perplexity and Google's AI features, September 2026
Concentration differs by engine. Google AI Overviews gives 38.5% of its citations to its own top 20 websites, while Perplexity spreads its citations most widely, giving its top 20 just 18.2%. Gemini and Perplexity are the engines where a smaller specialist website has the most room to be cited.
What this means for businesses and publishers
Match your effort to the engine. For Google's AI features, which cite YouTube and Reddit most, publish short videos that answer real customer questions and take part in the Reddit discussions about your field. For ChatGPT, which favors official and specialist sources, write pages with the precision of official guidance: exact figures, clear definitions and links to the primary source.
Then look at your own topic, not the pooled list. Ask the questions your customers ask in each engine and note which websites are cited; those are the sites to appear on or to outrank. Working with an ai seo company that tracks citation share across ChatGPT, Gemini, Perplexity and Google turns that check into a monthly routine.
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<p style="font:14px/1.5 system-ui,sans-serif">Source: <a href="https://www.suffdigital.com/resources/data-studies/top-cited-websites-in-ai">YouTube Tops AI Citations: Google's AI Cites It 6,894 Times vs 5 for ChatGPT - Suff Digital</a></p>
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Suff Digital. (2026). YouTube Tops AI Citations: Google's AI Cites It 6,894 Times vs 5 for ChatGPT. https://www.suffdigital.com/resources/data-studies/top-cited-websites-in-ai
YouTube Tops AI Citations: Google's AI Cites It 6,894 Times vs 5 for ChatGPT - Suff Digital - https://www.suffdigital.com/resources/data-studies/top-cited-websites-in-ai
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