SEO ranks a page. AEO extracts an answer from a page. GEO generates a new answer and, if you’re lucky, cites the page. That’s the actual mechanical difference between the three disciplines search marketers have argued about since roughly 2023. What hasn’t changed is the underlying test: is this source credible enough to point to, extract from, or quote. Three different retrieval mechanisms, one constant requirement.
(A quick note on spelling: I write “optimisation” the Australian way through this piece, and “Optimization” with a z in the acronyms — SEO, AEO, GEO — because that’s the fixed, capitalised term the industry and the search volume use. Not a typo, just two conventions living in one article.)
What Is SEO, Actually?
Search Engine Optimisation is the practice of getting a page to rank on a results page a human then scans and clicks. The mechanism is an index and a ranking algorithm: Google or Bing crawls a page, scores it against hundreds of signals, and returns an ordered list of ten blue links.
The term itself is older than most people doing it today. Several people arrived at “search engine optimisation” independently around 1995–1997 — Bruce Clay, John Audette, Bob Heyman and Leland Harden, and Viktor Grant among them — with Danny Sullivan, founder of Search Engine Watch, doing the most to popularise it from 1997 onward. An alternative term, “search engine positioning,” existed at the same time (Frederick Marckini used it in his 1999 book) and lost. “Optimisation” won because it described an ongoing practice, not a one-off placement.
That history matters here because the current SEO/AEO/GEO argument is a rerun. Search Engine Land traced the same “what do we call this” debate happening now around GEO and AIO, and the conclusion was that the acronym isn’t the innovation — the underlying mechanism is.
What Is AEO, and How Is It Different From SEO?
Answer Engine Optimisation is the practice of getting a passage, not a whole page, pulled directly into a featured snippet, a voice answer, or an AI Overview. The mechanism is extraction: the engine identifies the single best-matching passage on an indexed page and displays it close to verbatim, with a link back.
I’ve written the mechanics of this in more detail in what answer engine optimisation actually is. The short version: AEO still depends on a traditional index. Your page still has to rank well enough to be a retrieval candidate in the first place. AEO is a layer on top of SEO, not a replacement for it.
What Is GEO, and How Is It Different From AEO?
Generative Engine Optimisation is the practice of getting a source cited, or at least reflected, inside a novel piece of text an LLM generates in response to a prompt — a ChatGPT answer, a Perplexity summary, a Gemini overview. The mechanism is generation, not extraction: the model doesn’t display your sentence, it writes its own sentence and, if your content was retrieved and judged trustworthy enough, attributes a claim in it to you.
This is the mechanism I went into detail on in what generative engine optimisation is and why most content doesn’t get cited. The term was coined formally in a 2023 research paper, GEO: Generative Engine Optimization by Aggarwal, Murahari, Rajpurohit, Kalyan, Narasimhan and Deshpande, accepted to KDD 2024. The researchers built a benchmark called GEO-bench and found that adding citations, statistics and quotations to a passage could lift its visibility inside generated answers by up to 40%, with the effect varying by domain.
What Actually Changed Between the Three?
Three things, concretely:
- The unit being evaluated. SEO evaluates a page. AEO evaluates a passage. GEO evaluates a passage’s usefulness as raw material for a new sentence the model writes itself.
- Who does the writing. In SEO and AEO, the words the searcher reads are yours, either in full or extracted close to verbatim. In GEO, the words the reader sees are the model’s own paraphrase — your job shifts from “write the sentence they’ll read” to “write the sentence a model will want to paraphrase and attribute.”
- Where the click goes, or doesn’t. This is the part with the clearest data behind it. Pew Research tracked 68,879 real Google searches from 900 U.S. adults in March 2025 and found people clicked a traditional search result in just 8% of visits when an AI summary appeared, versus 15% when it didn’t — and clicked a link inside the AI summary itself only 1% of the time. The click, when a generative answer is involved, is increasingly optional for the reader and increasingly rare for you.
What Didn’t Change?
The credibility test. Every one of these systems — Google’s ranking algorithm in 1998, Google’s featured-snippet extraction from 2015 onward, an LLM’s retrieval-augmented generation today — is trying to answer the same underlying question: is this source good enough to stand behind. What counts as “good enough” has stayed remarkably stable: specific claims over vague ones, named sources over anonymous ones, evidence over assertion. The GEO-bench findings above are really a restatement of E-E-A-T (Experience, Expertise, Authoritativeness, Trust) with different plumbing underneath.
Distribution economics didn’t change either, in the sense that matters most: being cited by an AI answer still requires being crawled and indexed first. None of the three disciplines works if a bot can’t reach your content, read it and parse its structure. GEO doesn’t skip SEO’s technical foundation; it sits on top of it.
Do I Need a Separate Strategy for Each One?
No, but you do need to check a piece of content against three different questions before you consider it finished:
- Will this page rank well enough to be found at all? (SEO)
- Is there a single self-contained passage in here an engine could lift and quote directly? (AEO)
- Is there a specific, sourced claim in here worth an LLM attributing to me by name? (GEO)
One well-structured article can satisfy all three if it’s built with headers that ask the actual questions people type, answers that don’t need the rest of the paragraph to make sense, and numbers that are traceable to a primary source rather than “significant growth.” The commercial incentive to keep doing this properly is growing, not shrinking: Adobe Analytics reported AI-referred traffic to U.S. retail sites was up 138% year-over-year in May 2026, and up 1,324% since October 2024, based on more than a trillion tracked site visits. That’s a channel worth writing for deliberately, not by accident.
FAQ
Is AEO the same as GEO?
No. AEO extracts an existing passage close to verbatim, such as a featured snippet or a voice answer. GEO generates new text and, at best, attributes a claim within it to your source. AEO is closer to traditional SEO mechanically; GEO is a genuinely different retrieval-plus-generation pipeline.
Does GEO replace SEO?
No. GEO depends on your content being crawled and indexed in the first place, the same technical foundation SEO has always required. There’s no published evidence of a generative engine sourcing content it never indexed.
Which one should I focus on first?
SEO, if your technical foundation — crawlability, indexing, page structure — isn’t solid, since nothing else works without it. If that’s already handled, prioritise AEO and GEO together, since both reward the same self-contained, evidence-backed writing.
How do I know if I’m being cited by ChatGPT or Perplexity?
Check your referral traffic segmented by source in GA4 — chatgpt.com, perplexity.ai and similar will show up as referrers — or ask the tools directly with prompts related to your expertise and see whether you’re named. I cover practical checks like this in the GEO piece.
Is answer engine optimization just a rebrand of SEO?
Partly, and that’s not a criticism. The industry has relabelled itself at every retrieval shift since 1997, when “optimisation” beat out “positioning” as the term of choice. What’s different this time is that two of the three disciplines, AEO and GEO, can now show a reader an answer without ever sending them to your site.
I’ve spent the past two years running growth for a B2B AI SaaS platform where this distinction wasn’t theoretical: it showed up directly in the traffic mix, with +938% website visitors and +1,696% Google traffic growth in six months, and a 10x increase specifically in ChatGPT-referred traffic over the same period. That’s one company’s result, not a universal formula, but it’s what convinced me these three disciplines need to be checked separately rather than assumed to be the same thing wearing different acronyms. If you want a second pair of eyes on where your content is actually landing — ranked, extracted or cited — that’s what I do.
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