Last reviewed: May 24, 2026

What is GEO (Generative Engine Optimization)? Definition and business implications

GEO (Generative Engine Optimization) is the set of practices aimed at making content identifiable, trustworthy, and citable by generative answer engines (ChatGPT, Claude, Perplexity, Gemini, Google AI Overviews). It succeeds traditional SEO when users seek answers, not links.

GEO rests on three principles different from classic SEO. Citability: generative engines build their responses from short, self-contained sentences and paragraphs that can be extracted out of context. A page well-written for GEO is structured in citable information units, not in literary blocks. Topical authority: generative engines favour sources that cover a topic in a dense and coherent manner, rather than isolated pages. A complete glossary on a domain, or a series of interlinked articles, ranks better than a single page. Semantic markup: Schema.org (notably DefinedTerm, Article, FAQ) allows engines to understand the structure of a page and extract relevant elements. In 2026, AI Overviews is generalised on Google, and users frequently consult ChatGPT, Claude.ai, or Perplexity as an alternative or complement to classic search engines. GEO is no longer an option.

Concrete example

A B2B services mid-cap in France finds at the end of 2025 that 40% of its organic traffic now comes from AI sources (citations in ChatGPT, Perplexity, Claude.ai, Google AI Overviews), against 5% at the beginning of 2024. Three structuring adjustments have been undertaken. Redesign of product pages with citable answer sentences at the start of each section (30 to 50 words, self-contained). Construction of a 40-term business glossary with Schema.org DefinedTerm markup. Addition of an llms.txt file at the root of the domain, listing the key resources for AI crawlers. Over 9 months, citations in generative engines tripled, and visibility in Perplexity and ChatGPT became measurable for the first time.

Three implications

GEO transforms the very nature of web referencing. Three implications for the executive. First, organic traffic is shifting, not disappearing. A growing share of the user journey now happens in generative answer engines, upstream of clicks. Measuring only traditional Google traffic amounts to measuring traffic in decline. The right indicator in 2026 is presence in AI responses, regardless of the final click. Second, the editorial and technical skills required change. A good GEO writer produces dense, structured answer sentences, citable out of context. A good GEO developer masters Schema.org and semantic markup. These two profiles are distinct and complementary. Third, GEO is built over time. It takes 6 to 18 months to build the topical authority needed for regular citations by LLMs. Starting early is a structural competitive advantage.

Sources

Schema.org official specifications, DefinedTerm and DefinedTermSet, 2026. https://schema.org/DefinedTerm (accessed 2026-05-24)
Google AI Overviews documentation, Google Search Central, 2025. https://developers.google.com/search/docs/appearance/ai-features (accessed 2026-05-24)

← Back to glossary

What is GEO (Generative Engine Optimization)? Definition and business implications

Concrete example

See also

Further reading

Sources