How AI Search Actually Works: Query Fan-Out Explained

Google Search Console dashboard on a laptop in the SEO Agency Galway office

In the early days of SEO, plenty of agencies sold it as a magic trick. They talked about secret sauce, proprietary methods and some mysterious relationship with Google, and they charged a premium for the mystery. The uncomfortable truth was that many of them did not actually understand how the ranking algorithms worked. The mystique was the product.

That same playbook is being run again today, with a shiny new tool. Swap “Google’s secret algorithm” for “AI” and you get a fresh wave of specialists selling answer engine optimisation as a mysterious new discipline that only they understand. It is the same trick with a new coat of paint. So let us take the mystery out of it, because once you see how AI search actually works, the hype falls apart.

The simple version: AI does what a human would

Modern AI assistants are built to behave like a helpful person. So the simplest explanation of how they answer is also the most accurate one: an AI does what a human would do. Ask a person to recommend the best accountant in Galway and, unless they happen to know one already, they will not invent an answer. They will look it up. They will search, read a few pages, weigh what they find, and then make a recommendation.

An AI assistant does exactly this. It does not carry a live directory of every business in Ireland in its head. When you ask it something it cannot answer from memory, it goes and searches the web, reads what comes back, and builds an answer from that. The technical name for the searching part is query fan-out, and it is worth understanding properly. It also lines up with our wider point in GEO vs SEO: the two are the same discipline, not rivals.

What query fan-out actually is

When you put a question into ChatGPT, Gemini or Perplexity, the model rarely fires off a single search. Instead it breaks your question into several smaller, more specific searches and runs them together. That is the fan-out: one question fanning out into many queries.

Take a simple request: “who is the best plumber in Galway for an emergency callout?” Behind the scenes, the assistant might search for several things at once:

  • emergency plumber Galway
  • best plumbers Galway reviews
  • 24 hour plumbing Galway city
  • plumber near me Galway ratings

Each of those searches returns a page of ordinary ranked results, the same results a person would see. The assistant then reads across those pages, looks for the businesses and details that keep coming up, and assembles a short answer that names a few of them. It often shows its sources too, which is your clue that this whole process just happened.

The clues that fan-out is happening

It is not always obvious, but the signs are there once you know to look:

  • The answer includes citations or source links. Those are the pages it read.
  • Ask the same question twice and the answer can change. That is fresh retrieval, not fixed memory.
  • The businesses it names are, overwhelmingly, the ones that already rank in ordinary search for those terms.

That last point is the one that matters. If an AI assistant builds its answer from search results, then the way to be in the answer is to be in the search results, and to be described consistently wherever the assistant looks.

We summed this argument up on X. Here it is:

Why this makes “AEO” mostly SEO

Here is where the magic-trick sellers come unstuck. If the assistant is searching the web and reading what ranks, there is no separate dial to turn and no hidden “AI mode” to buy. Being the answer comes down to two things you already recognise: rank for the searches your customers make, and make sure every source that describes your business tells the same story.

The second half is worth dwelling on. An AI cannot independently verify that you are the best plumber in Galway. It can only measure whether the signals around your business agree: your website, your Google Business Profile, your reviews, your listings and your structured data all pointing at the same clear picture. Consistency is what it reads as trust. That is not a trick, and it cannot be faked into place with a magic package; it is the steady work of good SEO and clean, consistent signals. We break that work down on our AI visibility and GEO page.

The honest takeaway

If someone is selling you answer engine optimisation as a mysterious new service and cannot explain query fan-out in plain English, treat it the way you would have treated a 2005 agency promising to whisper to Google. The tool has changed; the sales trick has not. What genuinely moves your AI visibility is what has always moved your search visibility, done deliberately and measured honestly. If you want to see where you stand today, our AI visibility checker gives you the prompts to test it yourself, and the free SEO audit puts a real plan against it.

Michael McCormack, Digital Marketing Strategist at SEO Agency Galway

Written by Michael McCormack
Digital Marketing Strategist, SEO Agency Galway

Michael is a performance marketing strategist at SEO Agency Galway and its parent, Bubblehub Media. He owns the search and paid funnel end to end, from forensic keyword research and audience work to creative testing, so organic and paid pull in the same direction. . More about the team.

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