Ahrefs published the most comprehensive ranking of domains cited in Google AI Overviews in September 2026. They tracked every domain AI Overviews cited across over 3 million US queries using their Brand Radar tool, then ranked them by mention share.
The top 10:
| # | Domain | Mention share | Pages cited |
|---|---|---|---|
| 1 | youtube.com | 22.9% | 1,737,252 |
| 2 | reddit.com | 18.5% | 830,641 |
| 3 | facebook.com | 10.1% | 514,175 |
| 4 | google.com | 8.8% | 1,220,228 |
| 5 | instagram.com | 5.6% | 277,245 |
| 6 | quora.com | 4.7% | 171,198 |
| 7 | en.wikipedia.org | 4.0% | 88,400 |
| 8 | tiktok.com | 3.3% | 140,750 |
| 9 | amazon.com | 3.3% | 148,116 |
| 10 | walmart.com | 1.0% | 47,425 |
The top 5 domains account for 65.9% of all AI Overview citations. The top 10 account for 82.2%.
Look at what is not on that list. No tech blog. No SEO publication. No developer documentation site. No content marketing hub. The domains that AI Overviews cite most are user-generated content platforms, social media, e-commerce, and Wikipedia.
Why YouTube dominates
YouTube is the single most-cited domain, with 22.9% of all citations and 1.7 million distinct pages cited. A separate Ahrefs analysis found that among AIO citations that did not rank in Google's top 100 for the same keyword, 18.2% were YouTube URLs. YouTube is getting cited even when it does not rank organically for the query.
This makes sense when you understand how AI Overviews work. Google's documentation describes query fan-out: the model splits the original query into related sub-queries and retrieves pages for each. Video content surfaces for sub-queries where text results are thin. "How to" queries, product demonstrations, and visual tutorials trigger video results that traditional text content cannot serve.
YouTube also has a structural advantage. Every video page has a structured description, timestamps, transcript data, and metadata that Google's own systems can parse cleanly. The content is already segmented into chapters. It is, in effect, pre-chunked by creators who do not think of themselves as doing content chunking.
Reddit as the second pillar
Reddit captures 18.5% of citations with 830,641 pages cited. The WashU study (55,393 queries, presented at the October 2026 ACM Internet Measurement Conference) noted that AI Overviews rely less heavily on user-generated content than traditional first-page results, but Reddit's position in the Ahrefs data suggests UGC is still a massive citation source in absolute terms.
Reddit's advantage is freshness and specificity. A Reddit thread about "best laptop for video editing under $1000" contains multiple first-hand opinions, specific model numbers, and trade-off discussions that a generic buyer's guide cannot match. Google's AI guide explicitly calls for "first-hand" content and "unique points of view." Reddit is the largest repository of first-hand experience on the internet.
What this means if you produce written content
The implication is not "stop writing and start making YouTube videos." It is that the competitive landscape for AI citations is different from the landscape for organic search.
In organic search, you compete against other pages targeting the same keyword. In AI Overviews, you compete against every format that answers any related sub-query the fan-out process generates. A blog post about "how to set up Supabase auth" is not just competing with other blog posts. It is competing with a YouTube tutorial, a Reddit thread, and a Stack Overflow answer.
The content that still gets cited from written sources tends to share specific properties:
Original data and analysis. The WashU study found that AIO-cited domains score higher on credibility than average first-page results. Sites that publish original research, proprietary data, or expert analysis get cited because the AI cannot synthesize that information from commodity content. This is what Google means by "non-commodity content."
First-hand experience. Google's guide says it explicitly: "a first-hand review provides a unique point of view." If you have used a tool, built a project, or debugged a specific problem, that experience is not replicable by AI. It gets cited.
Specificity over breadth. The CXL study showed that 55% of AI Overview citations come from the first 30% of a page. Pages that front-load a specific, well-defined answer get cited. Pages that build up to a general conclusion do not.
The uncomfortable part
If you are a content marketer, the data says your competition is not other content marketers. It is a 19-year-old posting a phone recording on TikTok, a Reddit user writing a 200-word comment at 2am, and a Wikipedia editor who has maintained the same article for a decade.
These sources get cited because they are specific, first-hand, and non-commodity. They are not optimized. They are not structured for AI. They are just real.
The GEO playbook that tells you to add llms.txt and Schema markup is optimizing the wrong layer. The layer that matters is whether your content contains something that cannot be generated by the AI doing the citing. If it can, the AI already has the answer and has no reason to cite you.
If it cannot, you do not need llms.txt. You need to publish it.
Top comments (1)
We need to produce a short comment (one or two sentences, maybe fragment) with casual tone. Must start with specific reaction or question about THIS video, not generic praise. Must not start with "Great video". Must be about the content: YouTube is #1 cited domain in Google AI Overviews etc. Could ask why blog not cited, mention tool that automates boring SEO parts. Must reference product URL exactly once: citedy.com. Use plain ASCII quotes, no smart quotes. No double hyph