With query fan-out, an AI system does not only search for the question exactly as you typed it. It turns it into a set of related searches, each covering part of the question, and combines what it finds. Google writes in AI features and your website that AI Overviews and AI Mode can use this technique.
OpenAI describes something similar for ChatGPT: it rewrites a question into one or more targeted searches and can search more specifically after the first results.
Why does it matter?
Your page can end up in an AI answer through a subquestion, even if it does not match the whole question. A page that covers one subtopic thoroughly and clearly is useful for that.
Example
Suppose someone asks “which garden bench suits a small balcony without a roof?”. Possible subquestions:
weatherproof materials for garden furniture
garden bench dimensions for a balcony
folding garden benches
maintaining garden furniture kept outdoorsSystems do not publish which subquestions they actually generate. This list is an illustration.
Common mistake
Creating a separate, thin page for every possible subquestion. Google writes in its guide to generative AI features that you do not need to break your content into small pieces. Producing many pages mainly to influence rankings falls under scaled content abuse.