Are GEO, AEO, LLMO and AI SEO the same thing? Mostly yes, and here is the exception

Somebody has sent you a proposal. It offers Generative Engine Optimisation, or possibly Answer Engine Optimisation, or AI SEO, for a monthly fee that is not small. The deliverables list looks familiar in places and completely opaque in others. And the honest question you cannot easily ask out loud is: is this a new thing, or is this the SEO I was already paying for with a different word on the invoice?

Fair question. Here is the answer, and then the working.

Mostly, they are the same thing. GEO, AEO, LLMO and AI SEO describe overlapping work under competing labels. Three of the four have no fixed definition and no owner, which is exactly why every agency glossary you read contradicts the last one. Only one of them has a precise, traceable origin, and it did not come from an agency.

But there is one genuine difference in the pile, and it is not the one being sold to you. The work itself has barely moved. The way you measure it has changed completely.

The short version, if you only read this far

• GEO is the only term with a real definition, from a peer-reviewed academic paper in 2024. The industry borrowed the acronym and quietly dropped the method it described.
• AEO is older in spirit and aims at something slightly different: being the answer rather than one source cited inside an answer. That distinction is real.
• LLMO is barely used, and it collides with an unrelated engineering term that already owns the phrase.
• AI SEO carries two incompatible meanings at the same time, and most pages using it do not tell you which one they mean.
• Google’s own position is that optimising for generative AI search is still SEO. We agree with Google.
• What has genuinely changed is that you cannot see your own visibility any more. There is no rank tracker for a private chat window.

If you are holding a quote, the useful test is not which acronym is on the cover. It is whether the agency can tell you how they will measure the thing they are selling. Most of this post is about why that question is harder than it sounds.

GEO: the only one of these with a birth certificate

GEO stands for Generative Engine Optimisation. Before anything else, a quick disambiguation, because GEO already meant something in marketing: geographic. Geo-targeting and geo-modifiers, the whole local search vocabulary. If you have been in marketing more than five minutes, your first instinct on seeing “GEO” is location, and that instinct is now wrong about half the time. Two different concepts, one abbreviation.

Now the interesting part. GEO was not coined by an agency. It was coined in an academic paper.

“GEO: Generative Engine Optimization” was submitted to arXiv on 16 November 2023 by Pranjal Aggarwal, Vishvak Murahari, Tanmay Rajpurohit, Ashwin Kalyan, Karthik Narasimhan and Ameet Deshpande, and it was accepted to KDD 2024. That gives GEO peer-reviewed provenance that none of the other acronyms on this page can claim. You can read it yourself at arxiv.org/abs/2311.09735.

(The paper spells it “Optimization”, with a z. We are a UK business and use “optimisation” everywhere else, but a paper title is a paper title and we are not going to edit it.)

Here is what makes the origin worth knowing. The paper does not define GEO as a service category. It defines a black-box optimisation framework, a specific method that content creators can apply to improve how visible their material is inside generative engine responses, tested against a benchmark the authors built called GEO-BENCH. The abstract reports that their methods can boost source visibility by up to 40%.

That number gets quoted a lot. It deserves its caveat, so here it is: the 40% was measured on the authors’ own benchmark of roughly 10,000 queries, in a research setting. It is not a claim about what happens to a plumbing company in Bristol. Anybody quoting “up to 40%” at you without that sentence attached is quoting a benchmark result as though it were a commercial one.

So GEO began as a method with a measurement attached. What happened next is that the market kept the three letters and left the method behind. UK agencies now sell “GEO agency” as a service line, and in that usage the acronym means nothing more precise than “we will help you show up in AI”. The gap between what the paper defined and what the sales page offers is, to us, the single most interesting fact in this whole subject. The one term with a rigorous definition is used almost exclusively by people not using it rigorously.

AEO: being the answer, not being in the answer

AEO stands for Answer Engine Optimisation, and it has the strongest claim to being genuinely different from the others.

A note on its history first, because we would rather tell you what we do not know than guess. We could not find a dated primary source for when AEO was coined or by whom. The general impression from searching is that the term predates generative AI and grew out of featured snippets and voice assistants, but an impression from search results is not evidence, and we are not going to put a date on this page that we cannot stand behind. So: no coinage date for AEO. If you see one quoted confidently elsewhere, ask where it came from.

What AEO means is clearer than where it came from. It comes from a world of one-box answers and voice replies, where there is exactly one winner per question and your goal is to be that answer. One slot, one occupant.

That is a different target shape from what GEO aims at. In a generative answer, several sources get synthesised into a paragraph and cited. You are not trying to be the answer, you are trying to be one of the sources in it. That changes the goal, and changing the goal changes the tactics. Of the four terms, AEO is the only one whose distinction survives a hard look.

AEO is also the second most used of these labels in the real world. Across our own scan of UK agency websites, gathered for a companion study, AEO turned up in every single file we looked at. It has actual distribution. LLMO does not.

A note on our own numbers, since we will use them a few times below. We counted how often each of these terms appears across four scan files of UK agency websites, gathered on 13 September 2026 for a companion study. It is first-party data and it measures one specific thing: which labels UK agencies actually put on their own sites. One honest caveat. We assembled that corpus by searching for GEO agencies, so GEO is over-represented by construction and its raw count is an artefact of how we sampled, not a measure of preference. The comparisons worth anything are the ones between the terms we did not search for, and those are the only comparisons we make.

LLMO: the term with a squatter on its name

LLMO stands for Large Language Model Optimisation, and it has a problem that no amount of marketing will fix.

“LLM optimisation” already means something. In machine learning engineering, it means optimising the model itself, for inference speed, or cost, or memory footprint. It is an established phrase in a completely unrelated field. So somebody searching it may land in either world, and neither result set will make sense to the other audience.

We also could not identify who coined the marketing sense of LLMO, or when. No attributable first use turned up. And in live commercial use it is thin: across the four files in our scan of UK GEO agency sites, LLMO appeared three times in total, in only one of the four files. For comparison, AEO appeared in all four. You will also see the variant “LLMEO” in circulation, and the adjacent phrase “LLM SEO”, which is slightly more common than LLMO itself but not by much.

One more detail from that research, and it is a small thing that says a lot. In a scan of UK agencies in this category, the three domains that had to be rejected for having no contact details of any kind were all llm-prefixed brands. Businesses named after the newest piece of terminology were, in our sample, disproportionately thin on substance. That is one small sample and we are not going to pretend it is a law, but it is the kind of signal worth keeping in your head when a brand name is also a buzzword.

AI SEO: the phrase that means two opposite things

This one is not an acronym, it is a compound phrase, and it is the trap we would most like you to leave this page remembering.

“AI SEO” is currently used to mean both of the following:

1. Optimising your website so it shows up in AI search surfaces.
2. Using AI tools to do ordinary SEO work faster.

Same three characters. Opposite referents. One is about where your business appears, the other is about how your agency does its production work. And most pages ranking for the phrase do not tell you which one they mean, because the ambiguity is commercially convenient.

If you are reading a proposal and it says AI SEO, that is a question to ask before you read another line. “Do you mean you will make us visible in AI answers, or that you will use AI to produce the work?” Both are legitimate services. They are not the same service, and they are not worth the same money to you.

The two terms nobody is selling you but you should know

“AI visibility” is the sleeper of the whole group, and it is our pick for the phrase to actually use in conversation. In our scan it appeared more often than “AI SEO” and far more often than LLMO, and it turned up in every file. It works as a service name and as a metric name. More to the point, it is the only label on this page that a non-technical buyer understands without being taught an acronym first. Nobody needs a glossary for “AI visibility”. That is not nothing.

GAIO, or Generative AI Optimisation, is worth mentioning only so you can discount it. Across our entire corpus of UK agency sites it appeared zero times. We saw an attribution for who coined it, could not verify it to a primary source, and are therefore not going to name anybody. Functionally, in the UK market, the term is absent.

You will also meet AIO and EIEIO, both of which have been spotted in circulation. AIO carries its own confusion, because AIO is also the common shorthand for Google’s AI Overviews, which is a product, not a practice.

And if the proliferation is starting to feel like the point rather than an accident, hold that thought, because the next section is about exactly that.

Why there are so many acronyms

There is a tidy explanation for terminology proliferation, which is that the field is subdividing into genuine specialisms and each one needs a name. There is also a less tidy explanation, which is that a new label is the cheapest way to sell an old service.

Three pieces of evidence point at the second one.

The first is the sheer count. Rand Fishkin, who founded Moz and has no stake in selling any of this, wrote on 30 May 2025: “I’m dumb enough about branding to recognize that AIO, AEO, GEO, LLMEO, and the other 15 I saw on LinkedIn today are not the way.” Fifteen competing labels spotted on LinkedIn in a single day is not a taxonomy forming. Fishkin’s own counter-proposal is to keep the letters SEO and redefine them as Search Everywhere Optimisation, and he credits Ashley Liddell of Deviation and Nikki Lam of NP Digital for that framing. You can read his argument at sparktoro.com.

The second is what practitioners with long memories say. Greg Boser, quoted by Roger Montti in Search Engine Journal on 21 January 2026: “We don’t need to come up with a bunch of new acronyms to continue to do what we do.”

The third is something we found in our own research, and it is our favourite detail in this entire post. When we scanned the UK agencies selling in this category, a recurring discovery tactic emerged: they publish “best GEO agencies in the UK” listicles about each other. Found, Passion Digital, ClickSlice, Tilio, Buried, NeuralAdX, Blue Array, Fourmeta, MadeByShape and Qoulomb all appeared in that pattern. A category whose members’ main visibility play is writing lists that contain their competitors is a category being manufactured rather than observed. That is our reading of it, not a published finding, but the pattern itself is straightforward to verify: search the phrase and see what comes back.

What Google says, and why we agree

Here is the strongest argument against this whole category, and we think you should hear it in full before we tell you what we think has actually changed.

Google publishes an AI optimisation guide on Google Search Central. The page was last updated on 10 July 2026, and it says this:

“From Google Search’s perspective, optimizing for generative AI search is optimizing for the search experience, and thus still SEO.”

The same page also says:

“You don’t need to create new machine readable files, AI text files, markup, or Markdown to appear in Google Search.”

And specifically on llms.txt, the file that a fair number of agencies will happily charge you to implement, Google says it will “neither harm nor help your site’s visibility or rankings”. The guide is at developers.google.com. If you want the mechanics of what llms.txt actually is and how it works, we wrote that up separately in our llms.txt guide, so we will not repeat it here.

This is the strongest card the sceptics hold, because it comes from the company that operates the surface everybody is selling optimisation for. If Google says optimising for its generative results is still SEO, an agency claiming otherwise needs a reason, and “we have a new acronym” is not a reason.

There is one more number on the sceptics’ side. Ahrefs published its own traffic data on 16 June 2025, written up by Patrick Stox: AI search accounted for 0.5% of their traffic over the preceding 30 days, and 0.3% year to date. Half a percent. It is hard to argue that a channel at half a percent of traffic justifies a separate discipline with its own retainer, and we are not going to try.

For the record, and because a post that only quotes sceptics is as lazy as one that only quotes vendors, the other side has its advocates too. Manick Bhan, in that same Search Engine Journal piece, argues: “GEO is not just SEO with a fresh coat of paint.”

So we concede the main point. The work is still SEO. Most of what a good GEO engagement does is what a good technical and editorial SEO engagement always did.

Now here is what we think has genuinely changed, and it is not what is on the sales pages.

What has actually changed

Three things, and only the third one is a genuine break with how search marketing has always worked.

1. People click less

This is measured, not asserted. The Pew Research Center studied the real browsing behaviour of 900 US adults in March 2025, in work by Athena Chapekis and Anna Lieb published on 22 July 2025, and reported by Danny Goodwin in Search Engine Land on 24 July 2025.

Where an AI summary appeared, users clicked through to a result on 8% of visits. Where no summary appeared, 15%. Only 1% clicked a link inside the summary itself. And 26% of users simply ended their browsing session after a page with an AI summary, against 16% without one. For scale, 18% of the searches sampled produced an AI Overview at all.

Read those numbers carefully, because they cut both ways. Click-through roughly halves when a summary is present. But the summary was present on fewer than one in five searches in that sample, and the study is US adults in one month of one year. It is good evidence of a direction, not a forecast for your sector.

2. The traffic that does arrive behaves strangely

Back to that Ahrefs post from 16 June 2025, the same one that gave the sceptics their half a percent. The other half of the finding is that the 0.5% of traffic arriving from AI search accounted for 12.1% of signups, roughly 23 times the conversion rate of their average visitor.

Patrick Stox’s own caveat is the part that makes the number honest rather than exciting: “users from AI search click links 75% less”. If people click far less often, then the ones who do click are heavily self-selected for intent. You are not seeing magic traffic, you are seeing a filter.

Two things to hold on to. This is one company’s data, it is a B2B SaaS product, and it is not a benchmark for a UK trade business or a professional services firm. And a very high conversion rate on a very small number is still a small number.

3. You cannot see your own visibility any more

This is the real change, and it has nothing to do with acronyms.

In classic SEO, visibility is observable. A rank tracker reports that you are in position four for a search term, it reports it on a schedule, and you watch the line move. Everybody involved is looking at the same reality.

In an AI answer, there is no position and no shared reality. The conversation happens inside somebody’s private chat session, which you will never see. The output is not deterministic, which means the same question can cite you on one run and not on the next, with nothing having changed. There is no rank tracker, and the entire reporting apparatus that SEO built over twenty years does not transfer.

Microsoft’s framing of the mechanics, quoted in that same Search Engine Journal article, is the clearest one-line description of the shift we have read: “ranking still happens, but it’s less about ordering entire pages and more about which pieces of content earn a place in the final answer.”

So the honest position, ours, arrived at from the evidence above, is this. The work is still SEO. The measurement is not. And a large part of this market is selling a metric it cannot actually produce.

What an agency does differently in practice

If the work is mostly the same, what does the “mostly” leave out? Four things genuinely change at the desk, and we would want to see all four in a proposal before paying a premium for the acronym.

Measurement becomes an active job rather than a report. Because there is no rank tracker, somebody has to build a prompt set: a fixed list of the questions your buyers actually ask, asked repeatedly across ChatGPT, Perplexity, Google’s AI Mode and Copilot, with the results logged. Because output varies between runs, what you record is a citation rate, not a position. That is a real piece of work with real hours in it, and it is the single most concrete difference on this list. An agency selling AI visibility without one of these is selling you a feeling.

The unit of optimisation moves from the page to the passage. Classic SEO ranks a page. An AI answer lifts a specific paragraph and cites it. Microsoft’s line about “which pieces of content earn a place in the final answer” is exactly this. What it means when you are actually writing: put the answer directly under the heading that asks the question, and make each paragraph stand on its own. Cut the throat-clearing. A paragraph that only makes sense once you have read the three before it cannot be lifted out and used.

Off-site work shifts from links to mentions. The old currency was a followed link from a relevant site. The emphasis now includes being named in context, in comparison pages and roundups and forum threads, whether or not there is a link attached. Which, you will notice, is exactly what those UK agencies writing listicles about each other are doing. They may be shameless about it, but they are not wrong about the mechanism.

Crawler access splits into two questions instead of one. Being crawlable by Googlebot is no longer the same thing as being fetchable by an AI assistant’s retrieval agent. They announce themselves with different user agents and arrive from different address ranges, and whatever bot-management product sits in front of your site may well treat them differently too. This one has teeth: during our own scanning of UK agency websites, several returned an HTTP 403 error to a plain client because of their bot protection. A site that blocks a simple request may also block AI crawlers, which means an agency selling AI visibility can be invisible to the engines it sells visibility in. We are writing that up separately, with the receipts.

What does not change, which is most of it

This is the part a proposal will not volunteer, so here it is plainly. The following all matter as much as they ever did, and none of them are new:

• Your site being crawlable and indexable
• Clean information architecture, so content can be found and understood
• Page speed
• Structured data
• Genuine subject expertise, written by someone who knows the subject
• Being cited and referenced by other credible sites
• Naming your own products and services in language a stranger would recognise

If the GEO deliverables list you are holding looks a lot like a technical SEO audit with a new cover page, that is because most of it is one. That is not necessarily a problem. A technical SEO audit is useful and yours may well be overdue. It is only a problem if you are paying a premium on the basis that this is a different discipline requiring different skills, when the line items say otherwise.

Five questions to ask the agency that sent you the quote

Everything above is sourced. This bit is not: it is our own view, built from reading a lot of these proposals. Treat it as opinion with reasons attached.

1. “Which acronym are you using, and what do you mean by it?” If the answer is a confident definition, good. If the answer is a confident definition that contradicts the last agency’s confident definition, that is expected and not a red flag on its own. If there is no definition, you have learned something.

2. “If this says AI SEO, do you mean visibility in AI answers, or using AI to do the work?” Ask it early. The two services have different value to you.

3. “How will you measure it?” This is the one that matters. Look for a prompt set, a named list of surfaces being checked, a repeat schedule, and a citation rate rather than a position. If the measurement plan is “we will monitor AI visibility”, ask what the number is called and how it is produced.

4. “How much of this list is technical SEO?” Not a trap, a scoping question. If most of it is, that may be exactly what you need, and you should be paying technical SEO prices for it.

5. “Can your own site be fetched by AI crawlers?” Slightly cheeky. Also, on the evidence of our own scanning, a question that a meaningful number of agencies in this category would fail.

Which term should you actually use?

Use GEO when you are talking to people in the industry. It has the most distribution, it has the only real definition, and it is the term your own market will search.

Use AEO when you specifically mean being the single extracted answer, which is a different goal from being cited inside a synthesised one.

Treat LLMO and GAIO as noise for now. They may grow. Today they barely register in the UK market.

And when you are explaining this to a colleague, your board or a client who does not want a vocabulary lesson, say AI visibility. It is the only phrase here that survives being said out loud to a normal person, and it names the thing you actually want.

The one-line version

Four acronyms competing to name one practice. Two of the distinctions between them hold up: AEO aims to be the answer where GEO aims to be cited inside one, and GEO is the only term of the four with a proper definition, which the market has quietly stopped using.

The work is still SEO. The measurement is not. If your agency can show you how they measure, the label on the invoice does not matter much. If they cannot, no acronym will fix that.

If you are holding a quote you cannot read, send it to us. We will tell you which parts are standard technical SEO, which parts are genuinely new work, and whether the measurement plan produces a number that means anything. No obligation, and we will tell you if the quote is fine.

Our approach to GEO and AI visibility

Sources referenced in this article: Aggarwal, Murahari, Rajpurohit, Kalyan, Narasimhan and Deshpande, “GEO: Generative Engine Optimization”, arXiv:2311.09735, KDD 2024. Google Search Central, AI optimisation guide, last updated 10 July 2026. Rand Fishkin, SparkToro, 30 May 2025. Roger Montti, Search Engine Journal, 21 January 2026, quoting Greg Boser, Microsoft and Manick Bhan. Athena Chapekis and Anna Lieb, Pew Research Center, 22 July 2025, as reported by Danny Goodwin, Search Engine Land, 24 July 2025. Patrick Stox, Ahrefs, 16 June 2025. First-party term counts from believe.digital’s own scan of UK agency websites, 13 September 2026.