What is query fan-out?
Query fan-out is when an AI search tool splits one question into many smaller searches, runs them at the same time, and writes one answer from the pages those searches return.
Cited from the66th.com/glossary/query-fan-out
How query fan-out works
A person asks one question. The AI tool breaks it into the smaller questions a careful researcher would look up, searches each one, reads the pages that come back, and writes a single answer that cites a few of them.
The question
Which SEO agency should a SaaS company in Vancouver hire?
The searches it runs
- SaaS SEO agencies in Vancouver
- Reviews of SaaS SEO agencies
- What SaaS SEO costs per month
- SaaS SEO case studies
- In-house SEO or an agency for SaaS
- How to choose an SEO agency
The answer
One written answer that names a few agencies and links the pages it relied on.
- Agency location page
- Pricing guide
- Case study
The pages that win are the ones that answer a sub-question well, even when they rank nowhere for the original question. A pricing guide can be cited in an answer about which agency to hire, because pricing was one of the searches.
Where it happens
Google named the technique when it launched AI Mode: AI Mode uses query fan-out, breaking a question into subtopics and issuing many searches at once, and Deep Search runs the same technique at a larger scale. AI Overviews and assistants such as ChatGPT also search the web before they answer.
What it means for your business
Ranking for your main search is no longer the whole job. An AI answer about your service is assembled from the pages that answer its follow-up questions: what it costs, how you compare, who you have done it for, and whether you serve the buyer's area.
If those pages exist on your site and are written clearly enough to quote, the answer can draw on you. If they only exist on competitors' sites, it draws on them. This is the core of our generative engine optimization service.
Common mistakes
- Writing one long page that tries to answer every variation of the main search. Each sub-question is better served by a page built for it.
- Hiding prices, service areas or results in images or PDFs. An AI tool reads the text on the page.
- Judging AI visibility from one question. Ask the full set of buyer questions, the same way each month.
Related terms
Source: Elizabeth Reid, Google, AI in Search: Going beyond information to intelligence, 20 May 2025.