· 6 min read · Jason Youngjin Koh
SEO, GEO, AEO: what changed
Google's own documentation says GEO and AEO are rebranded SEO. A few things did genuinely change, and the people selling you the new labels are usually not talking about them.
Google's published position is that optimising for generative AI search is still SEO, and that AEO and GEO are new labels for work you should already be doing. So when an agency sells you generative engine optimisation as a separate service with a separate invoice, the first question is simple: what will they do that a competent SEO would not?
That is the short answer. A few things genuinely did change, though, and they are worth your time, because they are usually not what the new labels are being sold on.
Is GEO a different discipline from SEO?
No. Three questions decide whether an AI answer cites you, and they are the same three that decide whether you rank. Can a crawler fetch the page. Does the page answer the question in plain language, early. Does anything outside your own website corroborate what you claim. Every framework being sold under a fresh three letter name reduces to those.
The new labels have done one useful thing. They forced attention onto work a lot of agencies quietly skipped. Structured data was easy to treat as optional when the only reader was a ranking algorithm. It matters far more when the reader has to work out which company you are before it can describe you. Answering the question in the opening paragraph was always good practice. It became load bearing once the opening paragraph is the part that gets quoted.
| Sold to you as | What it actually means | Where the work sits |
|---|---|---|
| GEO | Making pages machine readable and quotable | Technical SEO and content |
| AEO | Answering the question directly and early on the page | Content structure |
| Entity optimisation | Making your business identifiable and described consistently | Structured data and off site profiles |
| AI visibility audits | Checking whether engines can fetch and quote you | Crawlability and rendering |
| llms.txt | A file no major engine reads | Nowhere useful |
What actually did change?
Three things. Google now runs two generative surfaces that behave differently from each other. Several engines outside Google read your site directly and do not execute JavaScript. And an answer can satisfy a searcher without a click, which changes what is worth measuring.
Only the third of those is a strategy problem. The first two are engineering problems, and they are cheaper to fix than most owners expect.
Why do AI Mode and AI Overviews cite different pages?
Because they are two separate citation engines that usually arrive at the same conclusion by different routes. Ahrefs compared hundreds of thousands of query pairs across both surfaces and found the answers agreed most of the time while the sources cited did not.
13.7%
How often AI Mode and AI Overviews cited the same URLs, across 540,000 query pairs (Ahrefs)
In the same research, the two surfaces averaged around 86% semantic similarity across 730,000 response pairs. Nine times out of ten they said the same thing and credited different people for saying it. Two practical consequences follow. A report showing you inside AI Overviews tells you very little about AI Mode. And any agency quoting a single AI visibility number is flattening two different systems into one figure.
Do you need an llms.txt file?
No. There is no public evidence that it earns citations, and there is a reasonable amount of evidence that it does nothing at all. Anyone selling you one cannot point at a study showing it works, because no such study exists.
- Google's guide says explicitly that you do not need new machine readable or AI text files to appear in Search, and that adding them will neither help nor harm your visibility.
- Gary Illyes said publicly that Google does not support llms.txt and is not planning to. John Mueller compared it to the keywords meta tag, which search engines abandoned decades ago because it was trivial to abuse.
- SE Ranking studied roughly 300,000 domains and found no relationship between having the file and being cited in major AI answers. Their prediction model got more accurate when they removed llms.txt as a variable.
Building one takes an afternoon and does no damage. Paying for one, or accepting it as a deliverable inside a monthly retainer, is paying for a file nothing reads. If it appears on a proposal, treat it as a signal about the rest of the proposal.
What actually moves AI citations?
Six things, roughly in order of leverage. None of them are new, and all of them are SEO.
- Serve real text in the raw HTML. If your page builds its content in the browser, most AI crawlers receive an empty shell and nothing else you do matters.
- Answer the question in the first 40 to 60 words of the page, and again at the top of each section. Quotable passages get quoted.
- Say plainly what your business is, in one sentence, and repeat that sentence identically everywhere it appears.
- Give a machine facts it can verify: a registered business number, an address, a language, a real price, a named founder.
- Earn mentions on sources the engines already trust. Directories, industry press, client sites, podcast show notes, anything with an editor.
- Keep publishing pages that answer one specific question properly, rather than long pages that answer six questions vaguely.
Coverage and structure beat depth here. A 1,200 word page that answers a question cleanly and states its facts plainly gets cited more often than a 4,000 word guide that buries the answer in the middle.
What should you ask before you buy GEO services?
Five questions. They take two minutes and they will tell you most of what you need to know about whether the work is real.
- What does my site serve to a crawler that does not run JavaScript? A good answer includes a number, and they should have checked before the meeting.
- Which surfaces are you measuring, separately? AI Overviews, AI Mode, ChatGPT, Perplexity and Copilot are not one number.
- What sentence will define my business, and where will it live? If there is no single definition sentence, there is no entity work happening.
- What is the deliverable in month one? If the answer is an llms.txt file or an AI readiness score, ask what changes on the site.
- What are you going to stop doing? Budget that moves to GEO has to come from somewhere, and it should not come from the things that already work.
We publish what we find while doing this work on our own site and our clients', including the parts that did not work. More from ScaleMaster
The honest summary
The label on the invoice changed. The work mostly did not. What changed underneath is that a set of technical fundamentals that used to be forgiving are now unforgiving, because a system that cannot read your page cannot describe your business, and a system that cannot identify your business will describe someone else's. Fix those and the acronym on the proposal stops mattering.