AI search

AI search is search in which a generative AI model reads web results and writes an answer to the query, usually with links to its sources, instead of returning only a ranked list of pages. Examples include Google AI Overviews and Google AI Mode, the search features in ChatGPT, Perplexity, Microsoft Copilot, and Gemini and Claude when they search the web.

Why it matters

AI search reaches very large audiences. At I/O 2026, Google said that AI Overviews has over 2.5 billion monthly active users and that AI Mode passed 1 billion within a year. Each answer names a few brands and cites a few pages, so being named inside it matters as much as ranking below it.

The pages AI search cites are often not the pages that rank. In a 2025 Ahrefs study of 15,000 long-tail queries, only 12% of the links cited by ChatGPT, Gemini and Copilot appeared in Google's top 10 for the same prompt. Perplexity came closer, with 28.6% of its cited links in the top 10.

How it works

Most AI search systems retrieve pages first, then generate the answer from them, a pattern called retrieval-augmented generation. Google says AI Overviews and AI Mode may also run several related searches at once, which it calls query fan-out. To be used, a page has to be reachable by the engine's crawler and present in its index; Google requires that a page be indexed and eligible to show with a snippet.

How to measure it

Measure AI search in three places:

• The answers: run the prompts buyers ask and log who is named and cited (prompt tracking).
• Search Console: its Generative AI performance report counts impressions of your links in AI Overviews and AI Mode.
• GA4: the AI Assistant channel shows visits from AI assistants.