A citation is the reference to a source in an AI answer, as a link, footnote or source card pointing to a specific URL. It is the result of the entire selection chain: the page was found in the initial retrieval, a passage passed the re-ranking, the grounding snippet was used for the answer, and the model marked it as evidence.
How does a citation arise?
The model synthesises the answer from several snippets. A source is cited when its snippet carries a statement that appears in the answer: a figure, a definition, a recommendation. Snippets that merely repeat what other sources also say go into the answer without being cited. What is citable is therefore what contributes something of its own (information gain).
Why do citations matter for AI visibility?
Citations are the proof that your content shapes the answer. They arise almost exclusively through grounding, that is, through your own website, unlike mentions, which mostly arise through third-party sites and model knowledge. But: cited is not visible. A citation rarely brings notable traffic (zero-click), and a source far down in an expanded list has hardly any presence. The value lies in the role as evidence and in the authority that builds from it over time.
What does this mean for your website?
Provide passages that carry a statement nobody else provides: your own data, concrete figures from experience, clear definitions with numbers. Structure them so that they work as a snippet. Measure the citation rate with your prompt set and evaluate which third-party sites are cited frequently in your topic area. You need to be present there as well (source analysis).