SEO, AEO, GEO, IAO: The Complete Search Stack

Search stopped being one game years ago. Today a customer might find you through a ranked link, a boxed answer, a voice reply, or a recommendation composed by their AI assistant — and each of those moments is won by a different discipline. Here is the whole stack in one place, and the part that comes after it.
The stack at a glance
| Layer | Wins | Audience | The prize |
|---|---|---|---|
| SEO | The ranked link | Search engines | Organic human traffic |
| AEO | The extracted answer | Answer engines, voice | The zero-click moment |
| GEO | The mention | Generative AI (Grok, Claude, ChatGPT, Gemini) | The recommendation |
| IAO | The ingestion | AI crawlers | Clean data inside every AI system |
| Operability | The task | The user's own agent | The completed signup, purchase, setup |
Each layer in one paragraph
SEO makes you findable. Content that answers real queries, authority links, technical health. Still the foundation — AI answers are built largely from pages that already rank. Full explainer →
AEO makes you the answer. Question-shaped headings, self-contained passages, honest FAQs — the structure answer engines lift straight into overviews, snippets and voice replies. Full explainer →
GEO makes you recommended. A consistent entity footprint, citable original material, topic authority — so conversational models name you when someone asks for the best option. Full explainer →
IAO makes you ingestible. Semantic structure, clean hierarchy, llms.txt, machine-readable data feeds, deliberate AI-crawler access — the technical blueprint that feeds every layer above. Full explainer →
Why they work together
None of these replaces another — each builds on the one below. Ranked pages feed the answer engines; structured answers feed the models; clean data feeds them all. Dropping one layer weakens the rest: brilliant GEO with blocked AI crawlers is a book the reader cannot open; perfect IAO with no authority is a library nobody visits. The strategy is one stack, worked in parallel.
The rung the stack is missing
Follow the stack to its end and notice what every layer has in common: they optimize how you are found, quoted, cited and understood. All of it ends at the moment of decision. Then the customer's assistant has to actually do something — sign up, buy, configure — and description runs out.
That last step is operability: a published, consent-gated operational layer that lets a user's own agent adopt and operate your service, exactly as you defined. They optimize to be found. We make you operable.
One link that feeds the whole stack
This is the practical shortcut: the "Share with my agent" link works every layer at once. Shares move through social feeds and chats — the engagement signals SEO rewards. The layer declares your facts in clean, quotable form — AEO material by construction. Users keep handing their assistants the same link, and every resolution reads the same declared facts — the repetition and consistency GEO cites. The layer itself is structured, machine-readable data at a stable address — IAO done for you. And on top of all four, it is the one asset that lets the assistant act.
Start where every audit should: run the free scan — it scores your site across these layers in about a minute. Then publish your first page with the Free plan: one URL, free.
FAQ
Do I need all four disciplines?
You need to not fail at any of them. Depth where your customers actually are, hygiene everywhere else — and the scan shows you which is which for your site.
Where does a small business start?
With the two free checks: the site scan and the AI-crawler test. Most small sites discover quick wins in IAO and AEO before spending anything on the slower layers.
Is operability really separate from the stack?
It answers a different question. The stack decides whether you are found and trusted; operability decides whether the task completes on your site. One is visibility, the other is conversion — which is why we treat it as the layer on top, not a fifth flavor of the same thing.
Ask your AI about this article
Paste this into Grok, Claude, ChatGPT, Gemini — or any AI assistant — and ask it to check it:
swa:1:aHR0cHM6Ly9zaGFyZXdpdGhteWFnZW50LmFpL2Jsb2cvdGhlLWNvbXBsZXRlLXNlYXJjaC1zdGFjay5qc29u
Keep reading
What Is AEO? Answer Engine Optimization, Explained
AEO wins the zero-click moment — AI overviews, voice replies, featured snippets. How answer engines pick their answer, and how to make it yours.
What Is GEO? Generative Engine Optimization, Explained
GEO gets your brand synthesized, cited and recommended inside AI conversations — Grok, Claude, ChatGPT, Gemini. How citation is earned, and what feeds it.
What Is IAO? Information Architecture Optimization, Explained
IAO structures your site's data so AI systems can ingest, map and cite it — semantic schema, clean hierarchy, llms.txt, machine-readable feeds.