SEO vs GEO vs AEO: what's the difference?

You will hear SEO, GEO and AEO used as if they were three official products with three separate algorithms. For a UK small-business owner, that framing is usually unhelpful.

They are overlapping industry labels, not a menu of separate ranking systems. Google does not publish a “GEO score.” OpenAI does not sell an “AEO pack.” What helps customers find you is still familiar: make important pages crawlable, clear and useful, and keep business facts accurate.

This article explains how people use the terms, what major platforms publish for site owners, and how to prioritise work without buying three parallel retainers.

There is a worked local example in the Brighton plumbers ChatGPT vs Gemini study (eight questions, five chats per tool, 6 November 2026), which shows how the same prompts can produce different shortlists.

Quick definitions

Term	How agencies often use it	What to anchor on instead
SEO (Search Engine Optimisation)	Improve visibility in classic search results (Google, Bing, etc.)	Crawl, index, rank and present pages for search queries — Google Search Essentials / How Search Works framing; Bing’s webmaster guidelines
GEO (often “Generative Engine Optimisation”)	Improve chances of being cited or used in AI-generated answers	Platform-specific eligibility: e.g. Bing discusses grounding/citation eligibility; Google’s AI Overviews/AI Mode sit on Search systems; ChatGPT search has its own crawler rules
AEO (often “Answer Engine Optimisation”)	Optimise for featured answers, voice answers or Q&A-style results	Clear pages that answer questions; structured data only where it matches visible content; still no universal “answer engine” algorithm

Bing’s Webmaster Guidelines use GEO in an educational sense: they describe generative engine optimisation as focusing on content eligibility for grounding and reference in AI responses, and they note that SEO does not guarantee rankings or traffic, and GEO does not guarantee grounding or citations.

Treat GEO/AEO as goals about how answers are assembled, not as proof of a new secret ranking lever.

What the major platforms publish for site owners

Google Search, AI Overviews and AI Mode

Google’s Search Central guidance on AI features says:

• Best practices for SEO remain relevant for AI Overviews and AI Mode.
• There are no additional technical requirements and no special schema or AI text files required to appear in those features.
• To be eligible as a supporting link, a page must be indexed and eligible to appear in Google Search with a snippet.
• Meeting requirements still does not guarantee crawling, indexing or serving.

Separately, Google’s Google-Extended robots token lets publishers manage whether crawled content may be used for training future Gemini models and for grounding in Gemini Apps / Vertex AI. Google states that Google-Extended does not impact inclusion or ranking in Google Search.

So improving how you appear in Google’s AI answers in Search is largely the same work as being a clear, crawlable Search result — plus keeping Business Profile or Merchant details accurate where relevant. A longer, practical version is How to appear in Google AI Overviews.

ChatGPT search

OpenAI documents OAI-SearchBot for surfacing sites in ChatGPT search features, separate from GPTBot (training-related crawling). Eligibility means allowing the search bot and published IP ranges; placement is not guaranteed.

That is search-style retrieval and citation behaviour, not the same control surface as Google AI Overviews. Details: How to get your business recommended by ChatGPT. For the Business Hub dashboard OpenAI launched for claimed businesses, see ChatGPT now has a Business Hub: what it means for UK businesses.

Bing, Copilot and grounding

Bing’s guidelines tie classic SEO fundamentals to eligibility for Bing search experiences, Copilot and grounding API results. They emphasise discovery (sitemaps, IndexNow, links), clean canonicals, correct robots/noindex use, and clear, focused content. Manipulative tactics can reduce ranking and grounding visibility.

Again: overlapping foundations, not a third unrelated sport.

Perplexity and others

Perplexity documents PerplexityBot for search-result surfacing (not foundation-model training). Assume different products, different bots, and a shared need for public, accurate pages.

Crawling, indexing, ranking, training — keep the words straight

• Crawling — a bot fetches URLs (subject to robots.txt and network access).
• Indexing — a system stores and organises content it may later retrieve.
• Ranking / selection — choosing what to show for a query or which sources to cite.
• Training — using content to improve a foundation model (often a separate opt-out from search crawlers).
• Grounding / retrieval-augmented answers — pulling current sources at answer time so a model can cite or lean on them.

You can allow search crawling while restricting training crawlers where a platform offers separate tokens (OpenAI’s OAI-SearchBot vs GPTBot; Google’s Search crawl vs Google-Extended preferences). That is a publishing preference, not an SEO shortcut.

Where the work actually overlaps

Most of what helps across SEO and AI-answer eligibility looks ordinary:

1. Technical access — important URLs return successfully; robots and CDN rules allow the crawlers you care about; no accidental noindex on public pages. See Why isn’t my website showing on Google?.
2. Clear entities and facts — consistent business name, location or service area, services and contact details on the site and, where eligible, Google Business Profile.
3. People-first pages — pages that answer the questions customers ask, with visible text (not only images or PDFs crawlers struggle to use).
4. Sensible structure — titles, headings and internal links that make the main topic obvious.
5. Honest evidence — process, credentials, photos and specifics you can stand behind — not fabricated case studies.

Structured data can support understanding when it matches visible content. Markup alone is not a visibility switch, and misleading markup is a problem on both Google and Bing.

How to prioritise

Use this sequence unless you already have evidence a later step is the bottleneck.

1. Fix “can we be found at all?”

• Google Search Console coverage for key URLs
• Clear robots, noindex and canonical issues on public pages
• GBP eligibility and accuracy if you are a local business

If Google cannot index you, Google’s AI features in Search cannot use you as a supporting link either.

2. Fix “do we deserve the click or citation?”

• Service pages that state who you help, where, and what happens next
• Local landing pages only where you truly serve the area
• Content that resolves confusion (pricing approach, timelines, exclusions)

This is classic content marketing territory — usefulness first.

3. Then widen AI-search hygiene

• Confirm OAI-SearchBot / other relevant bots are not blocked unintentionally
• Keep facts consistent across the web properties you control
• Review whether training opt-outs are a deliberate choice

An AI search audit sits here: checking eligibility and clarity across assistants after the foundation is stable.

4. Skip vanity work that does not change eligibility

• Guarantees of AI citations or pack rankings
• Separate “GEO content” that rewrites the same thin page for robots
• Paying for reviews or other tactics banned by Google
• Schema-only projects with no substantive page underneath

One solid website beats three buzzword workstreams. If budget is tight, spend it on access, accuracy and customer-led pages.

A simple decision guide

• Most leads still come from Google Search/Maps? Prioritise technical SEO, local profile accuracy and service content.
• Customers mention ChatGPT or other assistants? Keep search foundations, then verify search-bot access and answer-worthy pages.
• Someone proposes a full “AEO rebuild” first? Ask which concrete control (robots token, indexing eligibility, content change) will be different on Monday — and what you will measure.

Browse the services overview for how these pieces fit commercially.

Short Q&A

Is GEO replacing SEO?
Google’s AI features guidance frames existing SEO fundamentals as the path into AI Overviews and AI Mode, not a separate replacement product.

Do we need different content for each acronym?
Rarely. Write for customers once; make sure machines can fetch and understand that same content. Adjust format only when a page fails a real user task.

Can anyone guarantee AI citations?
No. OpenAI, Google and Bing each state in their own words that placement, indexing/serving or grounding/citations are not guaranteed.

Next step

If you want a single pass that separates crawl/index issues from answer-eligibility issues, start with an AI search audit, keep publishing useful content, and use the wider services overview to pick only the work your evidence supports.

Sources

• AI features and your website (Google Search Central) — SEO fundamentals for AI Overviews/AI Mode; no special schema/AI files
• Google’s common crawlers — Google-Extended vs Search inclusion/ranking
• Overview of OpenAI Crawlers — OAI-SearchBot vs GPTBot
• Searching the web with ChatGPT — eligibility and placement
• Bing Webmaster Guidelines — SEO fundamentals for grounding; GEO as eligibility focus
• Perplexity Crawlers — PerplexityBot for search surfacing