SEO, AEO and GEO are three names for optimising the same content for three kinds of result. SEO aims for a position among Google's links. AEO aims to be the direct answer, the one the engine shows or reads out without the user clicking. GEO aims to be cited inside an answer generated by a language model, such as ChatGPT or AI Overviews.
In day-to-day work they overlap for the most part. Google says so openly. At WordCamp US in August 2025, Danny Sullivan said: "Good SEO is good GEO, or AEO, AIO, LLM SEO". A few days earlier John Mueller had been blunter on Bluesky: "The higher the urgency, and the stronger the push of new acronyms, the more likely they're just making spam and scamming".
The differences are real, but smaller than many agencies make out. They're mostly about what you measure.
The three acronyms in one table
| SEO | AEO | GEO | |
|---|---|---|---|
| Full name | Search Engine Optimisation | Answer Engine Optimisation | Generative Engine Optimisation |
| Goal | Rank among the results | Be the answer that's shown | Be cited or named in the generated answer |
| Where you see it | Google and Bing results pages | Featured snippets, People Also Ask, voice assistants, AI Overviews | ChatGPT, Gemini, Perplexity, Claude, AI Mode, AI Overviews |
| What you measure | Rankings, clicks, conversions | Presence in snippets, answers won | Citations, brand mentions, share of voice |
| Talked about since | The 1990s | 2017-2018 | November 2023 |
SEO
SEO is the foundation of all three. A site that Google can't crawl, index and understand doesn't get into the classic results or into generated answers either, because AI Overviews and AI Mode take their sources from the same index.
Google's documentation on AI features and your website, updated in December 2025, is explicit: to appear as a link in AI Overviews or AI Mode a page has to be indexed and eligible to show a snippet, and "there are no additional requirements". You don't need special files or dedicated markup.
If you're starting from scratch, our beginner's guide to SEO is the place to begin.
AEO
The term Answer Engine Optimisation has been around since 2017-2018, when Google multiplied featured snippets and voice assistants read out a single answer. Jason Barnard claims to have introduced it with a whitepaper for Trustpilot and an article on Search Engine Watch. The attribution is his own.
In practice AEO works on the shape of the answer: explicit questions in the H2s, a one-sentence definition right below, lists and tables that can be lifted out. It's the work that wins featured snippets and it helps in generated answers too. The full guide is in what answer engine optimisation is. Watch out for the acronym: in the UK "AEO" is also HMRC's Authorised Economic Operator customs status and the Association of Event Organisers. "aeo" gets 4,400 searches a month on Google UK, and on 10 October 2026 only one of the ten organic results on page one (Seobility) was about answer engines: the rest were about customs or events.
GEO
GEO has a precise birth certificate: the paper "GEO: Generative Engine Optimization" by Aggarwal and others, published on arXiv in November 2023 and presented at KDD 2024. The Princeton researchers tested nine ways of rewriting a text to get it cited more often by generative engines. The results:
- adding quotations, statistics and sources increases visibility by up to 40%;
- on the live Perplexity the gain reaches 37%;
- keyword stuffing makes the result worse than the original text.
GEO adds two things to SEO. First, reputation off your own site matters, because the models are happy to cite Reddit, Wikipedia, YouTube and trade publications. Second, it's measured differently, because a citation in ChatGPT doesn't always bring a click. The full definition is in what generative engine optimisation is, the head-to-head with SEO in GEO vs SEO.
LLMO, AIO, AI SEO: synonyms and marketing
Besides the three main acronyms you'll come across:
- LLMO (Large Language Model Optimisation): a synonym for GEO, used mostly by people selling tools;
- AIO (AI Optimisation): an umbrella term, sometimes also used for AI Overviews, which causes plenty of confusion;
- AI SEO or SEO for AI: the name clients use when they ask for the service;
- agentic SEO: the newest, with two different meanings that we explain in agentic SEO.
There's no verifiable date of origin for LLMO and AIO. They're market labels.
How much the UK market searches for them
We pulled monthly search volumes on Google UK with DataForSEO on 10 October 2026. Average for the last 12 months (September 2025 to August 2026), with the change compared with the same month a year earlier:
| Keyword | Searches a month in the UK | Change in a year |
|---|---|---|
| seo geo / geo seo | 1,000 | -18% |
| generative engine optimization | 880 | -55% |
| geo vs seo | 590 | -34% |
| generative engine optimisation | 390 | -56% |
| answer engine optimization | 320 | -19% |
| seo and geo | 260 | +86% |
| aeo vs geo | 210 | +420% |
| seo aeo geo / seo geo aeo | 110 / 70 | n/a |
| agentic seo | 40 | n/a |
For comparison, in the US "generative engine optimization" gets 4,400 searches a month and "aeo vs seo" 1,900, against 880 and 210 in the UK. The full names peaked in September 2025 ("generative engine optimization" at 1,600, "answer engine optimization" at 480) and by August 2026 had fallen to 590 and 170, while the comparisons between acronyms ("seo and geo", "aeo vs geo") are growing. The numbers are still small: the people searching for these acronyms mostly work in the trade. The label with the most demand is "ai seo", at 1,900 searches a month and £34.09 a click. Businesses search for something else: how to show up in ChatGPT, what AI Overviews are, why their traffic is falling.
Where they overlap and where they don't
The work the three have in common, in our experience on B2B projects:
- a technically sound site that's fast and crawlable;
- content that answers real questions, with data and sources;
- a clear structure: one question per section, the answer straight below;
- structured data where it's needed;
- authority, in other words E-E-A-T.
What really changes with GEO:
- outside sources carry more weight. An Ahrefs study of 75,000 brands found that brand mentions on the web are the factor most correlated with appearing in AI Overviews (0.664), far more than backlinks (0.218). It's a correlation, not proof of cause, but it shows where to look. We cover it in AI citations and mentions;
- answers change with every request. SparkToro measured that the chance of two answers giving the same list of brands is less than one in a hundred. There's no point talking about a "ranking" on ChatGPT;
- the click is no longer the only metric. You measure citations and mentions, as we explain in the guide to AI visibility.
What to measure for each
- SEO: rankings, impressions and clicks from Search Console, conversions from GA4.
- AEO: presence in featured snippets and People Also Ask for question queries, impressions in Search Console's AI report.
- GEO: the share of answers in which the brand appears across a fixed sample of questions, repeated over time; traffic from GA4's AI Assistant channel; citations of your own domain.
Where to start
If the site has technical problems or weak content, GEO can wait: you start with SEO. If the SEO is solid, the next step is to measure where the brand shows up in AI answers today, with a sample of 30-50 questions your customers really ask. Only then does it make sense to decide what to work on.
It's the same order we follow in our GEO service: measurement first, then work on the site and on outside sources.
Frequently asked questions
SEO optimises to rank among search engine results. AEO optimises to be the direct answer the engine shows, such as a featured snippet. GEO optimises to be cited or named in answers generated by models such as ChatGPT, Gemini or AI Overviews.
No. Danny Sullivan said in August 2025 that good SEO is also good GEO, and Google's documentation says there are no additional requirements beyond SEO for appearing in AI Overviews and AI Mode.
Hardly. AI Overviews and AI Mode take their sources from Google's index, and ChatGPT and Perplexity also search the web before answering. A site that doesn't get indexed properly is left out of both.
Large Language Model Optimisation. It's a synonym for GEO used mostly by companies selling monitoring software.
