GEO (generative engine optimization) is the work of getting onto the cited side of generative answers such as ChatGPT, Perplexity and AI Overviews. It overlaps heavily with SEO, but because the goal is being cited rather than ranked, the criteria for decisions change. If you cannot tell which crawler collects training data and which builds a search index, a single blocking rule can remove you from answers altogether.
An execution log from our own iOS app site, where 93% of app referrals already came from ChatGPT while robots.txt was blocking that very crawler, and a method for redesigning brands and campaigns now that AI takes part directly in how customers discover, compare and buy.