Generative Engine Optimisation
GEO vs SEO: what actually changes when AI writes the answer
The answer
SEO earns you a ranked position and a click. GEO earns you a place inside the answer itself — the brand an AI engine names, the source it cites, when a buyer asks a question. The foundations overlap almost completely. The selection systems don't: the overlap between what Google ranks and what AI engines cite has collapsed to under 20%, so being good at one no longer means being visible in the other.
Every second call I take starts with some version of the same question: “We already pay for SEO — isn’t this GEO thing just SEO with a new invoice?”
It’s a fair question, because half the industry is treating it exactly that way. The honest answer is more useful than either extreme. GEO is not a rebrand of SEO, and it’s not a replacement for it either. They are two selection systems sitting on top of the same web, and in the last two years they have quietly stopped agreeing with each other.
This essay is the comparison I wish existed when I started running GEO engagements: what genuinely carries over, what genuinely changes, and what the evidence — not the sales decks — says about where your effort should go.
Same web, two selection systems
SEO optimises for a ranking pipeline. Google crawls, indexes, scores, and returns an ordered list of links. Your job is to earn a high position; the user does the reading and the choosing. Success is a click.
GEO optimises for a generation pipeline. An AI engine — ChatGPT, Perplexity, Gemini, Google’s AI Overviews — retrieves a handful of sources, synthesises them, and writes the answer itself. The user often never sees a list at all. Success is being inside the answer: named as the recommendation, or cited as the source.
That difference sounds academic until you look at what it does to the funnel. In a ranked list, position three still gets traffic. In a generated answer, there is no position three. The engine names three to five brands, and everyone else doesn’t exist for that query. It’s closer to winning a pitch than winning a ranking.
SEO is a contest for position. GEO is a contest for inclusion.
What stays the same
Let’s give SEO its due before the comparison, because the foundations transfer completely — and any GEO pitch that tells you to abandon them is selling you something.
Crawlability and technical health
AI engines discover the web with crawlers, the same way search engines always have. If GPTBot, PerplexityBot or Google-Extended can’t fetch your pages — because your robots.txt blocks them, your pages render everything client-side, or your site is simply slow — nothing downstream matters. A decade of technical SEO discipline is directly reusable here.
Content that actually answers something
Google has spent years rewarding content that demonstrates experience, expertise, authority and trust. AI engines want the same thing, arguably more literally: they need passages they can lift, attribute and defend. Thin content fails in both systems, for the same reason.
Entity clarity
Who you are, what you sell, where you operate — stated consistently across your site and the wider web. Search engines used this to build knowledge panels. Language models use it to decide whether they know enough about you to name you at all.
If you’ve done SEO properly for years, you are not starting from zero. You’re starting from the foundation — which is worth being clear-eyed about, because the foundation is also where the transfer stops.
What actually changes
Two systems reading the same web should mostly agree, and for a while they did. The overlap between Google’s top results and the sources AI engines cite used to sit around 70%. It has since collapsed to under 20% — and Ahrefs found that 28.3% of ChatGPT’s most-cited pages have zero organic visibility in Google. They don’t rank anywhere, and the model quotes them anyway.
Why did they drift apart? Three mechanical differences, each with a practical consequence.
Retrieval reads passages, not pages
Google scores pages against queries. A generative engine retrieves passages — chunks of text that can stand alone as evidence for a claim. A 3,000-word page that buries its answer in paragraph fourteen ranks fine and extracts terribly. This is why answer-first structure — the direct answer in the opening lines, one idea per section, questions as headings — went from a nice-to-have to the core of on-site GEO work.
Synthesis needs corroboration, not authority scores
Google trusts a page partly because of its link graph. A language model decides whether to name your brand based on whether independent sources agree about you. Your own site claiming you’re the best is one weak witness. A review platform, a Reddit thread and an editorial round-up all naming you in the same context is corroboration — and corroboration, not domain authority, is what crosses the threshold into a generated answer.
Authority is evaluated per query, not per domain
In SEO, domain strength compounds: a strong site lifts every page on it. AI engines behave more locally. They will happily cite a small specialist over a large marketplace on a specific, multi-constraint question — which is precisely why focused brands currently beat Amazon on long-tail buying queries, and why the discipline rewards depth in a niche over breadth across one.
The signals, compared
Here’s the cleanest way I know to show the shift. Ahrefs measured which signals correlate with appearing in AI Overviews across 75,000 brands. Branded mentions in authoritative publications: 0.664. Backlink count — the metric two decades of SEO was built on: 0.218.
The same pattern shows up in Muck Rack’s analysis of 25 million citation links: earned media — coverage other people wrote — accounts for roughly 83% of everything AI engines cite. The link itself matters less. Being talked about matters more.
| SEO optimises for | GEO optimises for |
|---|---|
| Keyword rankings on a results page | Being named inside generated answers |
| Backlink volume and domain authority | Branded mentions in publications engines cite |
| Click-through rate from a list | Share of voice across a prompt set |
| Page-level relevance to a query | Passage-level extractability |
| Domain strength that lifts every page | Per-query authority, corroborated by third parties |
| One engine that dominates | Four-plus engines that disagree with each other |
That last row deserves a sentence. ChatGPT, Perplexity, Gemini and AI Overviews share roughly 11% of their citation domains. Winning one buys you almost nothing in the others — which is why measurement in GEO means running the same prompts across all of them, on a schedule, and logging who gets named. We’ve published exactly how we do that in the GEO Measurement Protocol.
What this does to your budget
Follow the evidence above and the budget conversation almost writes itself.
Keep the SEO foundation funded. Technical health, crawl access and genuinely good content serve both systems, and letting them rot to chase AI visibility is self-sabotage. This layer is mostly maintenance: cheap, boring, essential.
Shift the growth spend to where the citations come from. Earned coverage in the publications your engines already cite. Review volume and recency on the platforms your category lives on. Genuine presence in the communities — Reddit above all — where buyers compare options. Answer-shaped content on your own domain for the questions buyers actually ask. This is slower and less packageable than a keyword campaign, which is exactly why it’s underpriced right now.
And stop paying twice for the same work. The most common failure I see is a brand paying an SEO retainer and a “GEO retainer” that are both, on inspection, invoicing for the same schema markup and the same content briefs under different names. We audited 24 of the most repeated GEO claims against primary sources — fifteen are false — and the pattern in the GEO Claims Audit is consistent: the deliverables easiest to invoice are the ones with the weakest evidence behind them.
The work that moves AI citations doesn’t happen on your website. That’s why it’s not on most proposals.
So do you need both? Yes — as layers, not rivals
Here’s the framing I use with clients. SEO is the licence to operate: it keeps you crawlable, indexable, and credible to every machine that reads the web, and Google still sends more absolute traffic than every AI engine combined. GEO is the growth bet: a channel where answers are three to five brands deep, most categories are uncontested, and AI-referred visitors arrive pre-sold — they were recommended, not just found.
The brands getting this right in 2026 aren’t choosing between the two. They’re running one content and authority engine with two scoreboards: rankings and clicks on one side, citations and share of answer voice on the other. If your current partner can only show you the first scoreboard, that — more than any single tactic — is the gap. It’s the gap our GEO programme exists to close, starting with a free audit of where you stand on the second one.
If you want to see how a citation decision actually gets made inside these engines, the companion essay to this one walks through it: why ChatGPT recommends your competitor instead of you.
FAQ
What is the difference between GEO and SEO?
SEO optimises for a ranked list of links: you compete for a position and earn a click. GEO optimises for the generated answer itself: you compete to be the brand or source an AI engine names when it answers a buyer’s question. The foundations overlap; the selection systems and winning signals don’t.
Does ranking well on Google mean AI engines will cite me?
No. The overlap between Google’s top results and AI-cited sources has fallen from roughly 70% to under 20%, and about 28% of ChatGPT’s most-cited pages have no organic Google visibility at all. Rankings help indirectly; they don’t transfer.
Does GEO replace SEO?
No. They’re layers on the same foundation. Technical health, crawlability and genuinely useful content serve both. GEO changes the emphasis: third-party validation and extractable structure matter more, keyword positions and raw backlink volume matter less.
Which signals matter most for GEO?
Branded mentions in publications engines already trust correlate strongest with AI visibility — 0.664 in Ahrefs’ 75,000-brand study, versus 0.218 for backlinks. Earned media accounts for roughly 83% of all AI citations. On your own site, the highest-leverage work is publishing direct, extractable answers to real buyer questions.
Should I split my budget between SEO and GEO?
Keep the SEO foundation funded — it serves both systems. Shift the growth budget toward what moves citations: digital PR into cited publications, review velocity, community presence, and answer-shaped content. The mistake is paying twice for the same on-site work under two names.
How do I know if GEO is working?
Measure share of voice in AI answers directly: run a fixed set of real buyer prompts across ChatGPT, Perplexity, Gemini and Google AI Overviews on a schedule, and log which brands and sources get named. One run is a snapshot; six to eight weeks of runs is a baseline you can defend.