In one sentence
ChatGPT is a conversational AI service provided by the U.S. company OpenAI. It is one of the most widely used generative AIs in the world and a primary observation target for GEO measures.
What does it look like in practice?
For example, when a user asks ChatGPT:
"What are some recommended sales SaaS tools?" "I'm looking for a yoga studio near Tokyo Station." "How do I file a tax return for furusato nozei (hometown tax)?"
ChatGPT responds. Whether your company is cited in those answers determines marketing success or failure in the AI search era.