For most of the internet's history, search meant one thing: Google. Getting found meant ranking in the ten blue links. The discipline for doing that was SEO — Search Engine Optimisation — and it was straightforward enough that a single term covered the entire practice.
That is no longer the case. Users now get answers from AI assistants, voice devices, featured snippets, AI Overviews, and generative chatbots — many of which never send a user to a website at all. For agencies managing client visibility, optimising for the ten blue links is necessary but no longer sufficient. Three disciplines now need to run in parallel: SEO, AEO, and GEO.
Here is a clear, practical breakdown of what each term actually means, where they overlap, and how to know which one is failing when a client's visibility drops.
SEO — Search Engine Optimisation
SEO is the practice of improving a website's visibility in traditional search engine results pages — primarily Google and Bing — through a combination of on-page signals, technical site health, content quality, and external authority (backlinks).
Search Engine Optimisation (SEO) is the process of improving a website's ranking in organic search engine results. It covers on-page factors (title tags, headings, content), technical factors (crawlability, page speed, Core Web Vitals), and off-page factors (backlinks, domain authority). The goal is to increase the quantity and quality of organic traffic from search engines.
SEO remains the foundation of everything else. A site that Google cannot crawl, cannot index, or rates as low-authority cannot benefit from AEO or GEO optimisation regardless of how well its content is structured. The hierarchy is: technical SEO enables ranking, ranking enables visibility, visibility enables the other disciplines.
What has changed about SEO in recent years is not the fundamentals — it is the weight Google assigns to different signals. Core Web Vitals now directly affect ranking. Thin content written to target keyword density is penalised by machine learning classifiers. E-E-A-T (Experience, Expertise, Authoritativeness, Trustworthiness) is a framework Google's quality raters use to assess whether a page deserves to rank for queries where accuracy matters.
AEO — Answer Engine Optimisation
AEO is the practice of structuring content so that search engines and AI systems can extract direct answers from it and present those answers in featured snippets, People Also Ask boxes, voice search responses, and AI-generated answer summaries.
Answer Engine Optimisation (AEO) is the practice of formatting and structuring content so that search engines and AI assistants can identify and extract direct answers to user questions. AEO techniques include: structured data markup (FAQPage, HowTo, Speakable schema), concise definition statements, question-and-answer content formats, and clear heading hierarchies that match natural language queries.
The practical difference between a page that ranks at position 3 and a page that earns a featured snippet is almost always structural, not substantive. Both pages may contain the same information. The page that gets the snippet answers the question directly in the first sentence of a paragraph, uses a clear heading that matches the query, and keeps the answer under 50 words before elaborating. That is AEO.
Voice search makes AEO more important, not less. A voice assistant does not read out ten results — it reads one. That one is almost always the featured snippet. For clients whose customers use voice search (local businesses, recipe sites, how-to content, medical information), AEO readiness is a direct revenue signal.
AEO and SEO are not separate strategies. AEO is a layer added on top of SEO — a page needs to rank first before it can earn a snippet. But ranking without AEO-ready structure means leaving snippet real estate to a competing page that ranks below you but is better formatted.
GEO — Generative Engine Optimisation
GEO is the practice of structuring content, brand signals, and entity information so that large language models and AI search systems are more likely to cite that content when generating answers for users. Where AEO targets structured snippets within traditional search results, GEO targets citation in systems like ChatGPT, Google Gemini, Perplexity, and Claude.
Generative Engine Optimisation (GEO) is the practice of optimising content and brand signals to increase the likelihood that AI search systems (ChatGPT, Gemini, Perplexity, Claude) will cite that content when generating responses. GEO signals include: named authorship with verifiable credentials, specific and attributable factual claims, consistent entity mentions across multiple platforms, schema markup using schema.org vocabulary, structured Q&A content, and citation-ready statistics or definitions. GEO differs from AEO in that it targets AI generation systems rather than structured search result features.
The underlying mechanism of GEO is entity recognition and source credibility. Large language models are trained on large portions of the web and weight content from sources that appear consistently, specifically, and accurately across multiple contexts. A brand that appears in the same way — same name, same URL, same description — across its own site, social profiles, directories, and third-party mentions is more legible to AI systems as a real, trustworthy entity.
Practically speaking, GEO optimisation involves four things: making the brand entity clearly defined (who you are, what you do, where you are found), making content factually specific rather than vague, structuring content in formats AI models prefer to cite (definitions, statistics, step-by-step instructions), and building consistent mentions across platforms that train data includes.
Where the Three Overlap — and Where They Diverge
All three disciplines share a common foundation: quality content that clearly answers real questions. Where they diverge is in the specific signals they optimise for and the systems they target.
- SEO targets Google and Bing ranking algorithms — backlinks, Core Web Vitals, technical crawlability, and content relevance signals.
- AEO targets Google's featured snippet and People Also Ask systems — content structure, schema markup, and concise answer formatting.
- GEO targets AI language model citation systems — entity clarity, factual specificity, consistent brand mentions, and source credibility signals.
A page optimised only for SEO may rank well but never earn a snippet or AI citation. A page optimised for AEO but with weak technical SEO may have perfect structure but no ranking to drive traffic to it. A page optimised for GEO but with no AEO or SEO foundation may be cited occasionally in AI answers but drive no sustainable organic traffic.
The agencies gaining ground right now are the ones auditing for all three — identifying which discipline is the weak link for each client, and addressing them in sequence rather than treating them as alternatives.
How to Audit for All Three in a Single Report
Running three separate audits for each client — one for SEO, one for AEO, one for GEO — is impractical at agency scale. The more effective approach is a single comprehensive audit that covers all three disciplines and organises findings by priority.
A complete audit should check: on-page SEO signals and technical health, Core Web Vitals performance data, structured data implementation (which directly affects AEO), entity signals (brand consistency, sameAs declarations, which affect GEO), AI bot accessibility (whether GPTBot, ClaudeBot, and PerplexityBot can crawl the site), and content structure for featured snippet eligibility.
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