GEO glossary

AI citations

AI citations are the links and source references that AI assistants attach to their answers to show where information came from. ChatGPT, Perplexity, Google AI Overviews and AI Mode all cite web pages, and a cited page can earn visibility and clicks without ranking in Google's top 10.

Reviewed by Gareth Hoyle, Managing Director
Last reviewed 31 October 2026

How do the main platforms show citations?

Perplexity adds numbered footnotes that link to the original sources. ChatGPT search, launched on 31 October 2024, includes links to sources and a Sources button that opens a sidebar of references. Google AI Overviews show linked sources beside the generated text, and in August 2024 Google added a right-hand link display on desktop.

What is the difference between a citation and a mention?

A mention is when the answer names a brand. A citation is when the answer links to a page as evidence. A brand can be mentioned without being cited, for example when a review site is the cited source, and a page can be cited without its brand being recommended. Tracking both shows whether a brand shapes answers directly or only through third parties.

What gets cited?

Citations do not simply mirror Google rankings. In an August 2025 Ahrefs study of about 15,000 long-tail prompts, only 12% of URLs cited by ChatGPT, Gemini, Copilot and Perplexity ranked in Google's top 10 for the same prompt. Perplexity had the highest overlap at 28.6%. One reason is query fan-out: assistants search variations of the question rather than the exact prompt.

The 2023 GEO paper by Aggarwal et al. found that adding citations, quotations and statistics to a page increased how much of it appeared in generated answers. A page that states a fact plainly, attributes it and dates it gives an assistant something it can quote.

Example

Asked 'what does a loft conversion cost in the UK', an assistant might cite a builder's pricing guide, a homeowner forum thread and a national newspaper. A guide that gives a dated price range for each type of conversion offers a figure the assistant can quote. A page that only says prices vary offers nothing to cite.