> ## Documentation Index
> Fetch the complete documentation index at: https://docs.peec.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Most-cited domains by engine — top 5 sources per AI platform

> Peec's 30M-source analysis (Mar 2026) — Reddit and YouTube lead everywhere; Google's surfaces favor social (Facebook, Yelp), ChatGPT favors editorial (Forbes, Techradar), G2 only for Perplexity.

Each AI engine trusts a different top-source mix. From Peec's 30-million-source US analysis ([full study](https://peec.ai/blog/top-domains-cited-by-ai-search-analysis-based-on-30m-sources), Mar 2026), the top 5 cited domains per platform:

| Platform       | Top 5 sources                                      |
| -------------- | -------------------------------------------------- |
| Google AI Mode | YouTube, Reddit, Facebook, LinkedIn, Yelp          |
| AI Overviews   | YouTube, Reddit, Facebook, LinkedIn, Medium        |
| Gemini         | Reddit, YouTube, Wikipedia, Medium, PCMag / Forbes |
| Perplexity     | Reddit, YouTube, LinkedIn, Wikipedia, G2           |
| ChatGPT        | Wikipedia, Reddit, Forbes, Techradar, LinkedIn     |

Patterns worth acting on (Mar 2026 data):

* **Reddit and YouTube appear in all five platforms' top 5** — the only universal signals.
* **Google's AI Mode and AI Overviews favor social content** (Facebook, Yelp); **ChatGPT leans editorial** (Forbes, Techradar).
* **Wikipedia is strong for ChatGPT and Perplexity but absent from Google's top 5.**
* **G2 appears only for Perplexity** — relevant for B2B teams.
* Facebook blocks Perplexity's bots entirely (robots.txt), so Facebook presence is a dead end for that channel; it still matters as diversification on Google's surfaces.

Overall cross-engine ranking: [Most-cited domains in AI search](/research/most-cited-domains-in-ai-search).

**Source:** [Top domains cited by AI search: Analysis based on 30M sources](https://peec.ai/blog/top-domains-cited-by-ai-search-analysis-based-on-30m-sources), Peec (Tomek Rudzki), Mar 2026.