AEO vs SEO vs GEO: What Actually Differs in 2026

AEO, GEO and SEO in one table

AEO and GEO are used interchangeably; LLM SEO and AI SEO are other names for the same work. Google's AI optimization guide uses both terms and says that, from Google Search's perspective, optimizing for generative AI search is optimizing for the search experience, and thus still SEO.

What stays the same

Google's guidance on its AI features is short: the best practices for SEO remain relevant, there are no additional requirements to appear in AI Overviews or AI Mode, and a page must be indexed and eligible to be shown with a snippet to be a supporting link. It lists the fundamentals that still matter:

• Crawling allowed in robots.txt and by any CDN or hosting layer.
• Content findable through internal links.
• Important content available as text, supported by good images and video where relevant.
• Structured data that matches the visible text.
• Up-to-date Merchant Center and Business Profile details for products and local businesses.

Google also lists what you can ignore for Google Search: llms.txt files and other special markup (Google Search does not use them, and on 15 June 2026 it said they will not affect visibility or rankings either way), chunking content into small pieces, rewriting content just for AI, chasing inauthentic mentions, and special schema for AI features. Creating pages for every variation of a query to manipulate AI responses, it says, falls under its scaled content abuse policy.

What actually differs

1. You measure answers, not rankings

SEO reporting starts from a keyword's position. AEO reporting starts from a prompt: the question a buyer would type into an assistant. For each prompt and engine you record whether the brand was named, where it appeared in the answer, which competitors were named, and which URLs were cited. Because answers are generated fresh, each prompt needs to be run more than once before a number means anything.

2. More than one engine, and they disagree

A brand can be cited by Perplexity and absent from ChatGPT for the same question. Google's AI features are rooted in its core ranking systems, so Google SEO carries over to AI Overviews and AI Mode. Other assistants run their own search and fetching, so their answers can lean on different sources. Measuring one engine and assuming the others behave the same leaves most of the picture out.

3. Other crawlers decide whether you can be cited

Outside Google, each assistant documents its own agents. OpenAI says OAI-SearchBot surfaces sites in ChatGPT's search features, and that sites opted out of it will not be shown in ChatGPT search answers; GPTBot is its separate training crawler. Perplexity says PerplexityBot surfaces and links sites in its results and is not used for training foundation models. Anthropic lists Claude-SearchBot for search quality, Claude-User for user-initiated fetches and ClaudeBot for training. Blocking the search or user agents can remove you from those answers even when your Google rankings are fine. Google-Extended, by contrast, is a robots.txt token, not a crawler: it controls use of content for Gemini and does not affect Google Search.

4. A mention is not a citation

An answer can name a brand without linking to it, or cite a page without naming the brand that owns it. AEO tracks both separately, because they move for different reasons: mentions follow what third-party sources say about you, citations follow whether your own page is the clearest answer the engine can retrieve.

5. Clicks are no longer the whole outcome

A buyer can act on an answer without visiting your site. Search Console's generative AI performance report, rolled out to all sites on 31 August 2026, shows your impressions in AI Overviews and AI Mode; for other assistants, the only record is your own sampling of their answers.

What to do first

1. Fix the fundamentals Google lists: crawlable, indexed pages with the answer in text near the top.
2. Check robots.txt and your CDN for the search agents of each assistant your buyers use, not only Googlebot.
3. Write down 10 to 20 questions buyers actually ask and run them on each engine several times to get a baseline.
4. Rewrite the pages that should answer those questions so the direct answer comes first, with facts an assistant can quote.
5. Earn real mentions on the third-party pages the assistants cite in your category.
6. Re-measure on the same questions after a few weeks, and report shipped work separately from movement.

Where Fenn fits

Fenn does the AEO half of this list. It asks ChatGPT, Claude, Gemini, Perplexity and Grok your buyers' questions when you start a check and reports share of answers, share of voice, average position, sentiment, competitors and cited sources. Its readiness check covers AI-crawler access, llms.txt, structured data, answer-first content, freshness and internal links, and each failure becomes a fix with a ready prompt. It also drafts answer-first pages that flag facts only you can supply. You approve every change and publish it yourself. It does not do keyword research or rank tracking, so keep your SEO tools. Plans start at $29 a month, set up after a demo.

FAQ

Is AEO replacing SEO?

No. Google's AI features are built on its core search systems, and Google says optimizing for them is still SEO. AEO adds measurement and fixes for answers across several assistants on top of SEO, not instead of it.

What is the difference between AEO and GEO?

In practice, none. Both describe work to be named and cited in AI-generated answers, and Google's guide mentions both terms side by side and treats them as the same work.

Do I need an llms.txt file for AEO?

Not for Google: Google Search does not use llms.txt, and Google said on 15 June 2026 that it will not affect visibility or rankings. Other services may read it, so maintaining one is optional, not a ranking lever.

How do you measure AEO?

Run a fixed set of buyer questions on each assistant, several times, and record share of answers, share of voice, position in the answer, citations and sentiment against a dated baseline. For Google's AI features, add Search Console's generative AI performance report.