Intro
Ask an AI engine a question and it writes its answer from a set of web pages, which it lists as sources. Some of those pages are written by companies and publishers. Others are posted by people: a Reddit thread, a creator's YouTube review, a personal LinkedIn post.
Which kind an engine leans on changes what it says about your brand. If it draws on Reddit threads and creator videos, what customers post about you feeds into the answer. If it draws on brand and publisher pages, what you and the press publish matters more.
We looked at the sources five AI engines used to answer the same questions between October 12 and 25, 2026, across the questions Searchable customers track. For each engine, we measured the share of sources that were posted by individual users, and we checked who posted each page rather than relying on the platform it sat on.
Sources used by AI engines, October 12 to 25, 2026
- Google AI Overviews uses the most user-generated content: 8.6% of the sources Google AI Overviews used were posted by users, such as forum threads, creator videos and personal posts.
- Google AI Mode follows at 7.0%: user-generated content made up 7.0% of the sources Google AI Mode used.
- ChatGPT, Perplexity and Gemini rarely use user-generated content: it made up 1.1% of the sources ChatGPT and Perplexity used, and 1.3% for Gemini.
- YouTube and Reddit carry Google's user-generated sources: together they supplied 62% of the user-generated sources Google AI Overviews used and 69% for Google AI Mode.
- Reddit is almost all of ChatGPT's user-generated content: Reddit supplied 90% of the user-generated sources ChatGPT used, and 82% for Gemini.
- Half the forum and social pages AI engines use come from brands: between 44% and 50% of the forum and social pages used by Google AI Overviews, Google AI Mode, Gemini and Perplexity were posted by brands, publishers or the platform itself, and 24% for ChatGPT.
Table of Contents
Share of the sources each AI engine used that are user-generated content
Google's two AI search products use user-generated content far more than the chatbots do. In AI Overviews, one in twelve sources (8.6%) was a forum thread, a creator's video or a personal post. In ChatGPT and Perplexity it was one in ninety (1.1%).
Share of the sources each AI engine used that are user-generated content
Share of sources posted by individual users, October 12 to 25, 2026. Google's AI search in orange.
Gemini is also a Google product, but it behaves like the chatbots here, not like Google Search.
Which sites make up each engine's user-generated sources
The engines draw their user-generated content from different places. Google's AI search spreads it across YouTube, Reddit, Facebook and LinkedIn. ChatGPT and Gemini take almost all of theirs from Reddit. Perplexity splits between Reddit and LinkedIn.
Which sites make up each AI engine's user-generated sources
Share of each engine's user-generated sources from each site, October 12 to 25, 2026. Darker means a bigger share.
 AI Overviews | AI Mode |  Gemini |  ChatGPT |  Perplexity | |
|---|---|---|---|---|---|
| YouTube | 32.9% | 37.1% | 4.4% | 1.6% | 4.9% |
| 28.7% | 31.8% | 81.9% | 90.0% | 47.1% | |
| 14.1% | 10.1% | 0.6% | 0.4% | 0.6% | |
| 7.5% | 10.4% | 0.2% | 2.3% | 31.5% | |
| 6.2% | 1.6% | 0.9% | 0.0% | 0.6% | |
| Medium | 1.7% | 2.1% | 10.6% | 0.2% | 0.0% |
| Quora | 3.0% | 2.2% | 0.3% | 0.0% | 0.0% |
| Other forums and social sites | 6.0% | 4.7% | 1.0% | 5.5% | 15.3% |
YouTube
Reddit
Facebook
LinkedIn
Instagram
Medium
QuoraHow often a page on a forum or social site is really user-generated
A page on YouTube, LinkedIn or Facebook is not always posted by a user. Brands run their own YouTube channels and LinkedIn company pages, publishers post their videos, and Facebook now publishes its own answer pages. So we checked who posted each page in a large random sample of the forum and social pages each engine used.
Share of forum and social pages each AI engine used that were posted by users
Share of each engine's forum and social pages posted by an individual, not a brand, publisher or the platform, October 12 to 25, 2026.
ChatGPT's forum and social sources are mostly Reddit threads, which are user-generated by nature, so most of them pass. Google's include many brand YouTube channels, company LinkedIn pages and Facebook's own answer pages, so half of them do not.
What it means for brands
- Earn coverage from creators and communities if Google's AI search matters to you: YouTube and Reddit supply most of the user-generated sources Google AI Overviews and AI Mode use, so reviews by independent creators and genuine discussion in the communities where your customers ask questions feed into those answers.
- Treat your own YouTube channel and LinkedIn page as owned content: a brand's own channel is posted by the brand, not by users, so it does not stand in for what customers and creators say about you.
- For ChatGPT and Gemini, Reddit is the user-generated site that counts: it supplied nine in ten of ChatGPT's user-generated sources, so if user content matters for your category on ChatGPT, it is Reddit discussion.
See where AI engines get their answers about you
Searchable shows the pages AI engines use when your customers ask about your category, from Reddit threads to your own site, and tracks your brand across every major engine.
- See which pages AI engines use for your customers’ questions
- Find the Reddit threads and videos AI engines use in your category
- Track your brand across every major AI engine
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Questions brands ask about user-generated content and AI search
Where does AI get its information?
AI search engines write their answers from web pages they list as sources. Most of those pages come from brands, publishers and reference sites. User-generated content, meaning pages posted by individual users, made up 8.6% of the sources Google AI Overviews used and 1.1% for ChatGPT between October 12 and 25, 2026.
Does user-generated content help SEO and AI visibility?
For Google's AI search, user-generated content is a real part of what it draws on: 8.6% of AI Overviews' sources and 7.0% of AI Mode's, mostly YouTube and Reddit. For ChatGPT, Perplexity and Gemini it is a small part, between 1.1% and 1.3% of sources.
Does my brand's YouTube channel count as user-generated content?
No. A channel run by your brand is your own content. In our checks, brands' own YouTube channels were the most common page type that sat on a social platform without being user-generated.
Which AI engine uses Reddit the most?
As a share of all sources, Google's AI search: Reddit supplied 29% of the user-generated sources Google AI Overviews used and 32% for AI Mode. Within the small amount of user-generated content ChatGPT uses, Reddit dominates, at 90%.
Methodology
We analyzed 3.2 million pages that ChatGPT, Perplexity, Gemini, Google AI Overviews and Google AI Mode listed as sources for their answers between October 12 and 25, 2026, across the questions Searchable customers track. We kept brands tracked on all five engines, so every engine answered the same questions, and averaged across brands so no single brand outweighs the rest. Pages were first identified by platform, then by page classification.