AEO vs GEO vs SEO (and AIO, LLMO)

The 30-second answer: AEO vs GEO is a vocabulary question, and GEO vs SEO is the real one

SEO is being found and ranked by a search engine. GEO, AEO, AIO, and LLMO all mean being read and cited by an AI that answers questions. The four AI terms differ in who coined them and what they stress, not in what you do on Monday. The foundations are shared with SEO; what changes is the unit of success (a citation in an answer instead of a rank), what the page is rewarded for (quotable facts with dates and sources), and how you measure it (logs and audits instead of a rank tracker).

Read the table by column three. The terms were coined by different communities for the same job, which is why a proposal from an agency, a paper from a university, and a job posting in Tokyo can describe one checklist in three vocabularies. The last column is the only place they diverge, and it is a matter of emphasis, not of method.

The five terms

SEO (search engine optimization)

Google's own starter guide describes it as helping search engines understand your content. The product is a ranked list of links; success is a position on that list; the feedback loop is weeks, since Google says every change takes some time to be reflected. The discipline is thirty years old and has a settled toolset: Search Console, sitemaps, robots.txt, structured data.

GEO (generative engine optimization)

Coined in a paper of that title by Pranjal Aggarwal and colleagues, posted in November 2023 and published at KDD 2024. It defines the problem as increasing a page's visibility inside answers generated from multiple sources, and it measured which edits helped on a benchmark of 10,000 queries: adding citations, quotations, and statistics raised visibility by roughly 30 to 40 percent; keyword stuffing did little or nothing. The term with the most evidence behind it, and the default in English.

AEO (answer engine optimization)

An agency term that emphasises the direct answer rather than the engine. It was already in use for featured snippets and voice assistants before generative answers existed, which is why some practitioners treat it as the older, broader label and GEO as its AI-era subset. In current usage the two are interchangeable; the checklists are the same.

AIO (AI optimization)

The widest label: arranging web content so that AI systems understand and cite it correctly, whatever the system. It spread early in the Japanese web industry and is common there. It names a goal more than a method, which makes it the safest word when you do not know which assistant matters to the audience.

LLMO (LLM optimization)

AIO narrowed to large language models: ChatGPT, Claude, Gemini, and the assistants built on them. Also favoured in Japan. The narrowing is mostly rhetorical, since the AI systems people mean by AIO are in practice large language models; treat LLMO and AIO as the same word with a different audience.

One more term appears in every discussion and is not a strategy: llms.txt. The spec describes it as a file that provides information to help agents use a website, read on demand. It is a concrete step inside any of the labels above, not a label itself, and the complete guide covers it from that angle.

What is the same under every label

Google’s page on AI features and your website says there are no additional requirements to appear in AI Overviews or AI Mode and no new files or markup to add. The AI search crawlers from OpenAI, Anthropic, and Perplexity fetch the same HTML. So the foundation is the SEO foundation, under any name:

• Crawlable and indexable. robots.txt and the CDN allow the crawlers; the page is in the index with a snippet. Google lists this first.
• Content in the HTML as text. Googlebot renders JavaScript; nothing else documents that it does.
• One page, one question. Google says AI features may use query fan-out, running several related searches; a focused page is what each of them retrieves.
• Facts that agree everywhere. Structured data matching the visible text, old posts that do not contradict the current page, one description of the company.
• Internal links and a good page experience. Both on Google’s list, both older than any acronym.

What is actually different from SEO

The last row is the reason small sites should care about the vocabulary at all. In the controlled study, the same content changes helped lower-ranked pages more than top-ranked ones. That is a different economy from classic search, and it is true under every one of the four AI labels.

Which word to use, and when

• Writing in English for a technical audience: GEO. It has the paper, and readers can look it up.
• Talking to an agency or reading a proposal: expect AEO, and translate it to GEO in your head. Ask for the checklist; if it matches the shared-foundations list above, it is the same service under a different name.
• Working in Japan: AIO or LLMO are what colleagues will say. Use theirs.
• Explaining it to someone outside the field: skip the acronym. “Making sure AI assistants describe us correctly and cite our pages” is the whole idea.
• Choosing a vendor: never by label. A vendor who sells GEO and AEO as two products with two prices is selling the same checklist twice.

A useful habit when a new label appears: ask which of the two ideas it belongs to. If success is a position in a list, it is SEO under another name. If success is being read and cited when a machine answers, it is the second idea, and the five words above already cover it. In three years of new acronyms, no term has yet described a third thing.

Checking where you stand

Whatever the label, the first check is identical: can an AI crawler fetch your pages as text, and what does it find? A checker answers that in one pass and drafts the one file all five labels eventually ask for.

FAQ