A page can rank #1 yet not be cited by an AI Overview, and a page ranking lower can be the one quoted. AI engines synthesise across sources and pick what best supports a clear answer, which isn't always the top blue link. So the target expands from "rank the link" to "be the source the answer is built from".
This reframes measurement. Alongside positions and clicks, you track citation share: how often you're referenced in AI Overviews, ChatGPT and Perplexity. It also reframes value: a citation can build authority and awareness even when it doesn't produce a click — part of the "disappearing clicks" dynamic.
Strategically, you optimise for both. Strong rankings still help you get cited, but citation adds its own requirements — extractable answers, entity clarity and trust. That combined discipline is exactly GEO and the work behind AI visibility.