AI Engines

Deep dives into AI search engines: how each one retrieves, ranks, and cites — and how to optimize for it.

• ChatGPT Search

  ChatGPT Search is retrieval-augmented chat: ChatGPT fetches the live web only when the model decides to, so citations are sparser than Perplexity's. Its edge is distribution scale. The load-bearing GEO fact: OAI-SearchBot — not GPTBot — controls Search visibility.

• Google AI Overviews

  Google AI Overviews is the SERP-embedded engine: an AI summary block atop classic Google Search, grounded on the normal web index via query fan-out. The load-bearing GEO fact — there is no AI Overviews crawler. Googlebot controls eligibility; Google-Extended does not.

• Google Gemini

  Gemini is the Google-stack retrieval-augmented-chat engine: a chat model given a Grounding-with-Google-Search tool, conditional not SERP-embedded. It shares AI Overviews' Google index, but the GEO fact is inverted: Google-Extended is the control here.

• Perplexity AI

  Perplexity is an answer-engine-native generative engine: it retrieves the live web by default and ships every answer with numbered inline citations — the most citation-dense, transparent mainstream engine, and the live-engine baseline GEO research and field tests use most.