SEO vs AEO vs GEO: What's Actually Different (And What Isn't)

By the end of 2025, three acronyms had collided in every marketing meeting: SEO, AEO and GEO. They are not interchangeable, but they are not three separate jobs either. This post draws the line between what has genuinely changed in the AI search era and what is the same work under a new label.

The short version

• SEO (Search Engine Optimisation) — getting a page to rank in the traditional ten blue links on Google and Bing.
• AEO (Answer Engine Optimisation) — getting a passage, snippet or entity from your page used as the answer surfaced by an answer engine (Google AI Overviews, featured snippets, voice assistants, ChatGPT Search).
• GEO (Generative Engine Optimisation) — a term introduced in the 2024 academic paper "GEO: Generative Engine Optimization" (Aggarwal et al., Princeton) describing how to make your content more likely to be included and cited inside the synthesised response of a generative engine such as Perplexity, ChatGPT or Google's AI Mode.

The three overlap heavily. The underlying crawl, the underlying index, and most of the on-page work is shared. What changes is the unit of visibility and how you measure it.

What is genuinely the same

Strip away the marketing and the foundations have not moved:

1. The page still has to be crawlable. Google's Gemini, OpenAI's GPTBot/OAI-SearchBot and PerplexityBot all need to fetch HTML. If your robots.txt blocks them, no acronym helps.
2. Authority still compounds. Google's E-E-A-T (Experience, Expertise, Authoritativeness, Trust) framework is explicitly referenced in the Search Quality Rater Guidelines, and the same brand signals — backlinks from credible publishers, named authors with verifiable credentials, original research — are the strongest predictors of being picked by any of these systems.
3. Structured, scannable content wins. Clear H2/H3 hierarchy, short paragraphs, definition-first opening sentences, tables and lists have always helped featured snippets. They help AI extraction for exactly the same reason: they make the salient passage easy to lift.
4. Schema is a tax you should still pay. Article, FAQPage, HowTo, Product, Organization and Person schema disambiguate your content for any retrieval system.

If you have done classical SEO well, you are already 70% of the way to ranking in AEO and GEO contexts.

What is genuinely different

There are three real shifts. Everything else is marketing.

1. The unit of visibility has shrunk from a page to a passage

In classical SEO, the page is the unit. In AEO and GEO, the passage — often a single sentence or a 2-3 sentence chunk — is what gets surfaced. Google's Passage Ranking update (2021) was the early signal; AI Overviews and ChatGPT Search now retrieve at chunk granularity.

Practical consequence: every section of your article should be independently useful. If a reader (or a retrieval model) lands on the H2 "What is GEO?", the paragraph beneath it must define GEO without needing the introduction.

2. Citation is the new click

In SEO you optimise for a click. In GEO you optimise for being named in a response — often without a click ever happening. A 2024 study by BrightEdge found that AI Overviews appear on ~64% of medical, ~58% of B2B-tech and ~57% of educational queries, with average referral CTR materially below traditional rank-1 positions. The trade is brand impression and credibility surface, not raw traffic.

This forces a measurement change: track citation share in AI responses, not just SERP positions. Tools like Profound, Otterly, AthenaHQ and SE Ranking's AI Tracker now monitor this; you can also build a simple weekly check with a script that prompts ChatGPT/Perplexity/Gemini with your priority queries and parses out which domains they cite.

3. Entity completeness beats keyword density

Generative engines ground their answers in entities (people, products, places, concepts) and the relationships between them. The Aggarwal et al. GEO paper, after running 10,000 search queries across multiple generative engines, found that the highest-impact content interventions were:

• Citing sources and statistics in the content itself (+30-40% visibility lift)
• Quoting authoritative third parties
• Using fluent, confident language rather than padded prose
• Adding direct quotations to the text

Notice what is not on that list: keyword density, exact-match anchors, or thin "SEO copywriting" tricks. The era of writing for a keyword is over; you write for an entity and its claims, with receipts.

Mapping tactics to engines

Tactic	Classical SEO	AEO (Overviews / featured snippets)	GEO (ChatGPT / Perplexity / AI Mode)
Backlinks from trusted publishers	High	High	High
Schema markup	Medium	High	Medium
Clear H2/H3 with question-style headings	Medium	High	High
Definition-first paragraphs	Medium	High	High
Cited statistics and quotes	Medium	Medium	Very high
Original research / proprietary data	High	High	Very high
Author bio and credentials on page	Medium	Medium	Very high
Internal linking and topical depth	High	Medium	High
Exact-match keyword targeting	Medium	Low	Low
Allowing GPTBot/OAI-SearchBot/PerplexityBot	n/a	n/a	Required

How to measure each

• SEO: Google Search Console (impressions, clicks, average position), Bing Webmaster, rank trackers.
• AEO: GSC's "AI Overviews" filter (rolling out through 2025-26), plus snippet-share trackers. Watch for impressions rising while CTR falls — that is your overview cannibalisation signal.
• GEO: prompt-based citation tracking. Pick 30-50 priority queries, run them weekly through ChatGPT, Perplexity and Google AI Mode, and record which domains are cited and in what position. Build the baseline before you change anything; the variance is high week-to-week.

What to stop doing

• Stop writing 2,000-word "ultimate guides" that bury the answer. Define the term in the first paragraph under each heading.
• Stop optimising for one long-tail keyword per page. Cover the entity and its sub-questions.
• Stop hiding the author. AI engines disproportionately cite pages with a real, named author and a credible bio.
• Stop blocking the AI crawlers unless you have a clear legal or commercial reason. PerplexityBot, OAI-SearchBot and Google-Extended are how you become a citation.

The honest summary

SEO did not die. AEO and GEO are not separate disciplines that need a separate team — they are the same craft pointed at a wider set of surfaces. The work that wins in 2026 is the work that has always won: clear writing, real expertise, and content that earns the right to be quoted. The new bit is that you now have to measure whether you are being quoted, not just whether you are being clicked.

FAQ

Is AEO just a new word for featured snippets? Partly. AEO covers featured snippets, People Also Ask, voice answers and AI Overviews — anything where a single answer replaces the click. Featured snippets are a subset.

Do I need to write separate content for ChatGPT and for Google? No. The same well-structured, well-cited page can be picked by both. Tailoring is at the section level (clean definitions, cited stats), not the page level.

Will GEO replace SEO? No. Generative engines are built on top of a search index — Bing for ChatGPT, Google's own index for AI Overviews and AI Mode, a hybrid for Perplexity. If you do not rank, you are usually not in the retrieval set the model draws from.

What is the single highest-ROI change I can make today? Add an author bio with real credentials, and rewrite the opening paragraph of each H2 to be a self-contained definition with one cited statistic. That single pattern lifts citation rates across all three engines.

---

If you want help mapping this across your site, our SEO service handles AEO and GEO as part of the same workstream — we treat them as one discipline, not three.