SEO, LLMO, REO, GEO: Why so many acronyms?

For more than two decades, SEO (Search Engine Optimization) has been the cornerstone of every digital visibility strategy. It relies on a combination of on-site techniques (site structure, tags, content) and off-site techniques (backlinks, popularity, authority) to improve a site’s ranking on traditional search engines like Google’s SERPs.

With the rise of generative AI and integrated assistants (such as ChatGPT, Perplexity, or Google AI Overview – formerly SGE), this landscape has been shaken up. New acronyms are appearing: LLMO (Large Language Model Optimization), REO (Retrieval Engine Optimization), or GEO (Generative Engine Optimization), illustrating SEO’s evolution toward these new search interfaces.

But why so many acronyms? And more importantly, how do we make sense of them?

SEO: The foundational pillar of visibility

Contrary to popular belief, SEO is not “dying”, it is evolving. A business without solid traditional SEO cannot expect to succeed in GEO optimization, because the fundamentals remain the same: content structure, semantic relevance, domain authority.

That said, excelling in SEO does not guarantee strong visibility in generative engines. Top SEO performers are not always the most cited (see Article 9 on this topic).

AI-driven search engines no longer just display a list of links. They synthesize, select, and contextualize. This shift demands new content strategies, particularly in structuring data so that AI engines can recognize and reuse it.

What are LLMO, REO, and GEO?

LLMO, REO, and GEO refer to practices aimed at optimizing a brand’s presence in AI-generated answers.

Where SEO focuses on indexing and ranking, LLMO/REO/GEO focus on whether AI models recognize a source as trustworthy and relevant when generating a response. The goal: to be cited, whether it’s a site, brand, article, or product.

Concrete techniques include:

• Clear, structured, and didactic content (FAQs, guides).

• Natural, precise, and neutral language.
  Building a strong digital footprint: cross-mentions, multichannel presence, authority signals.

• Regular content updates.

But why distinguish them?

This is mostly a semantic distinction made by marketers, which some industry purists debate. The main argument is that LLM-powered assistants aren’t tied to search engine SERPs. But this isn’t entirely true: ChatGPT, a pure LLM, still uses Bing SERPs for answers (even in the free version), and Gemini relies on Google.

So, simply put: GEO, REO, and LLMO all point to the same thing today.

To complicate things a bit:

• LLMO (Large Language Model Optimization): Focuses on optimizing for pure LLM assistants (ChatGPT, Claude, Gemini), where users explore topics through conversation.

• REO (Retrieval Engine Optimization): Refers to retrieval-augmented models (RAG) that fetch information outside the LLM, on the web and cite it back (Perplexity, AI Overview, Bing Copilot). But note: they also rely on LLMs, since retrieval alone isn’t enough.

• GEO (Generative Engine Optimization): Covers both LLM and RAG systems, as well as AI search engines like Google AI Overview (built on Gemini).

In short: GEO > REO > LLMO. GEO is the broadest term and the one best used to describe SEO tailored for generative AI services.

Comparing SEO and GEO

Even though SEO remains the common foundation (quality content, authority, relevance), the logic diverges:

• SEO focuses on ranking, clicks, and traffic.

• GEO focuses on citations, trust, and conversions.
  
  

Here’s a simplified comparison:

Criteria	Traditional SEO	GEO / REO / LLMO
Main objective	Generate clicks through SERP ranking.	Be cited in AI-generated answers (AI Overviews, ChatGPT, Perplexity, etc.).
User context	User scans results and clicks a link.	User reads a direct AI-generated answer, often without clicking.
Key techniques	Keyword research, on-page optimization, backlinks, site speed, UX.	Structured content (schema, FAQs), entity coherence (brand, product), authority & trust signals, cross-channel presence.
KPIs	SERP ranking, CTR, organic traffic.	Citation frequency, brand mentions in AI answers, share of voice, lead generation & conversion.
Opportunities	Capture high-intent traffic, maximize Google visibility.	Gain visibility even without top rankings, reach users in new environments (chat, direct answers), position brand as a trusted source.
Risks	Google updates dependency, keyword competition.	Low CTR despite citations, AI hallucinations, measurement challenges.
Strategic path	Be clicked → traffic → conversion.	Be cited → credibility → conversion.

While the SEO foundation is still essential, the levers are shifting.
SEO, LLMO, REO, GEO, or even AEO - Answer Engine Optimization, (which we could have discussed, at the risk of making this article truly indigestible), all point to the same ultimate goal: visibility.
The fundamentals remain: quality, relevance, trust, structure, authority. But the tools, priorities, and methods are changing. SEO feeds GEO, but GEO is redefining the rules of the game.

FAQs

• Is SEO disappearing with the rise of GEO?

  No. SEO isn’t disappearing, it’s evolving. It remains the essential base (structure, content, authority), but GEO changes the outcome: the goal is no longer just clicks from SERPs, but being recognized, cited, and trusted directly in AI engines.

• What’s the difference between SEO and GEO?

  SEO aims for clicks through top rankings in Google. GEO (or REO/LLMO) aims for citations in AI-generated answers, even without clicks, in order to build credibility and drive conversions.

• GEO, REO, LLMO: are they really different?

  Not really. These are mostly semantic nuances:

  • LLMO targets AI assistants (ChatGPT, Claude).

  • REO targets retrieval engines (Perplexity, Copilot, AIO).

  • GEO covers both. GEO is the broadest and most accurate term.

• Why talk about new KPIs?

  Because CTR and traffic matter less in AI environments. Key metrics are now citation frequency, trust, and ultimately conversions.

• What types of content boost GEO visibility?

  Clear, structured, regularly updated content (FAQs, guides), written in natural language, supported by strong digital authority (cross-mentions, reputation, reliability).

• What are the main opportunities of GEO for brands?

  • Build credibility.

  • Capture higher-quality leads.

  • Diversify visibility beyond traditional SEO.