ChatGPT does not draw evenly from the web. It skews toward encyclopedic and reference sources: published analyses put Wikipedia at roughly 47.9% of its top citations. ChatGPT answers from model weights first and reaches for the web when the question looks fresh, local or specific. Its search index is Bing-derived, so a page Bing has never indexed is effectively invisible to it no matter how well it ranks in Google.
How ChatGPT actually decides
ChatGPT answers from model weights first and reaches for the web when the question looks fresh, local or specific. Its search index is Bing-derived, so a page Bing has never indexed is effectively invisible to it no matter how well it ranks in Google.
Its citations skew toward encyclopedic and reference sources: published analyses put Wikipedia at roughly 47.9% of its top citations. In practice that means the surfaces worth auditing first are Wikipedia, established news and reference sites, vendor documentation, G2 and review aggregators.
The method, in order
Start from the skew, not from your site. ChatGPT’s citations concentrate in Wikipedia, established news and reference sites, vendor documentation, G2 and review aggregators.
Separate the sources it cites from the sources it trusts silently. This engine frequently asserts without linking, so the citation list understates what shaped the answer.
Check your category specifically. Citation skew is a population-level finding; the sources for legal advice and for developer tooling are not the same, and only your own prompt set tells you which applies.
Audit whether you appear on the top sources at all, then rank the gaps by how hard each is to close: a subreddit comment and a Wikipedia citation are not the same amount of work.
Re-measure after each placement lands. ChatGPT’s volatility is moderate, answers to the same prompt drift week to week as the underlying index refreshes.
The honest caveat
It is the slowest of the six to notice a new page, because a Bing-derived index has to find you first. Sites that only ever submitted a Google sitemap routinely discover they are absent here.
Cituna checks ChatGPT daily alongside the other five engines, ChatGPT, Perplexity, Gemini, Claude, Grok and Google AI Overviews, on the $39 Starter, and pairs the result with Google Search Console so a change here can be tied to real clicks. We do not track Microsoft Copilot.
Drafted with AI assistance from our own research and Search Console data, and reviewed by Rahul A before publishing. Rules and prices change; check the linked official source before you act.