Wikipedia dominates ChatGPT’s sources, study shows

A new study has found that ChatGPT, Google's AI Overviews, and Perplexity AI cite wildly different sources of information, raising important questions for brands and content creators trying to stay visible in the age of AI.

According to a report by analytics firm Profound, ChatGPT relies heavily on Wikipedia, with nearly 48% of its top citations coming from the community-run online encyclopedia. Reddit comes in a distant second, making up just over 11% of citations within ChatGPT's top ten sources. 

Meanwhile, Perplexity leans hard into community-driven content, with almost half of its citations coming from Reddit alone. Google's AI Overviews, on the other hand, spreads its citations more evenly. Reddit still tops the list (21%), but YouTube (18.8%), Quora (14.3%), and LinkedIn (13%) all have a strong presence.

The study examined 30 million citations from August 2024 to June 2025. Profound's findings suggest that visibility in AI responses depends heavily on where and how content is published online. For example, being active on Reddit is crucial for appearing in Perplexity and Google's results, while Wikipedia remains the best bet for being picked up by ChatGPT.

Ultimately, Profound says there's no one-size-fits-all strategy. Brands need to tailor their content to the unique sourcing habits of each AI tool if they want to remain in the spotlight.