When most people think about AI search, they think about ChatGPT. It earned that mindshare honestly — it is, by some distance, the largest consumer AI surface in the world. But it is one of six engines a serious GEO strategy has to track.
ChatGPT (OpenAI) is the volume play. It serves the broadest mix of buyer intents, from casual product research to detailed comparison questions. If you only optimise for one engine, this is the one — but you'll miss the higher-intent traffic the others bring.
Google AI Overviews is the engine your buyers see whether they like it or not. It now appears above the organic results for the majority of commercial queries in the UK. Cited brands inside the Overview capture disproportionate attention; everyone below the fold competes for what's left.
Perplexity is the answer engine professionals trust most. Its UX exposes citations more clearly than any rival, which makes it the de facto due-diligence tool for B2B buyers. Citation density per visit is higher here than anywhere else.
Claude (Anthropic) is the enterprise favourite. Companies that have rolled Claude out internally — especially in legal, financial services and healthcare — are seeing employees ask it for vendor recommendations. The audience is smaller; the spend per query is meaningfully higher.
Gemini is Google's bet on the conversational future. It pulls heavily from the same content base as AI Overviews but with a chattier interface and growing integration into Workspace. As Workspace usage grows, Gemini grows with it.
Microsoft Copilot completes the set. Embedded across Microsoft 365 and Bing, it reaches the workforce that doesn't open a separate AI tab and may not even realise it's interacting with one.
Six engines, six audiences, six different ways your brand can be recommended — or skipped. Tracking just ChatGPT misses most of the picture. Tracking all six is how you build a defensible GEO position.