A study from Profound of OpenAI's ChatGPT, Google AI Overviews and Perplexity shows that while ChatGPT mostly sources its information from Wikipedia, Google AI Overviews and Perplexity mostly source their information from Reddit.
The study looked at 30 million citations across ChatGPT, Google AI Overviews, and Perplexity from August 2024 to June 2025.
The findings:
- ChatGPT's top source/citation for answers was Wikipedia at 47.9%
- Google AI Overviews top source/citation for answers was Reddit at 21%
- Perplexity's top source/citation for answers was Reddit at 46.7%
Here is the breakdown for Google AI Overviews that shows Reddit, followed closely by YouTube, then Quora, and Wikipedia only shows up at 5.7%:
Here is the chart for ChatGPT showing Wikipedia first, then Reddit at 11.3%:
Perplexity really favors Reddit:
Seems like, at least for now, Reddit really gets a lot of airtime across all three, but more so Google and Perplexity.
Forum discussion at X.
Update: The folks at ahrefs posted a similar study a few hours later but the results are kinda different.
