AI SEO GLOSSARY
What is an LLM?
An LLM (large language model) is an AI model trained on vast amounts of text to understand and generate language; it powers chatbots like ChatGPT, Claude and Gemini. It matters for your website because buyers now ask LLMs for recommendations, and the model's answer decides which brands they hear about.
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Updated 23 October 2026
What is an LLM in AI, and how do LLMs work?
Most LLMs are neural networks built on the transformer architecture and pre-trained to predict the next word. They are then fine-tuned to follow instructions and behave as assistants.
Trained on huge text collections, an LLM learns patterns in language well enough to summarise, translate, analyse and write. It does not look facts up by default: it generates the most likely answer from what it learned. That is why LLMs can hallucinate, stating wrong things confidently.
To reduce that, many assistants add retrieval-augmented generation (RAG): they search the web or a database first, then answer with sources. When ChatGPT search, Perplexity or Google's AI features cite a page, retrieval is what put that page in front of the model.
Is an LLM the same as AI? No: an LLM is one kind of generative AI, focused on language.
What is an LLM in SEO, and why does it matter for my website?
In SEO, LLMs are a new place to be found. Optimising so they understand, trust and cite your site is called generative engine optimization (GEO) or LLM SEO.
When someone asks an assistant for "the best accounting software for freelancers", the answer names a few brands and may link a few sources. If you are not among them, you are invisible in that conversation, whatever your Google ranking. Read what is GEO for the full picture.
| Classic search | LLM answers |
|---|---|
| Ten ranked links | One written answer naming a few brands |
| You compete for position | You compete to be mentioned and cited |
| Measured by rank and clicks | Measured by mention rate, sentiment and citations |
How to check and improve your visibility in LLMs, with an example
Ask the assistants your buyers' questions and record whether you are named. Digimetrics AI Mentions Tracker checks GPT-4o, Claude, Gemini, Perplexity and Google AI Overview in 2 to 5 minutes.
The AI mentions tracker reports mention rate, sentiment, citation rate, position and cited sources. In the official tutorial's sample (fictional brand Brightpath), 12 of 15 answers named the brand (80%).
Then make your site easy for LLMs to read. The llms.txt generator builds llms.txt and llms-full.txt, and the AI readiness check tests llms.txt, AI-bot access and structured data.
- Allow AI crawlers you want to be found by in robots.txt.
- Open key pages with a one-sentence answer and specifics, not slogans.
- Earn mentions on the review sites and publications LLMs cite.
QUESTIONS PEOPLE ASK
Frequently asked questions
Still unsure? Email support@digimetrics.ai and a person will reply.
Is an LLM generative AI?
Yes. LLMs are a type of generative AI that produces text. Image and video generators are other types.
Why are LLMs not deterministic?
They generate text by choosing among likely next words, often with some randomness, so the same prompt can produce different answers. That is why AI visibility should be measured across many runs and questions.
What is an llms.txt file?
A plain-text file at your site's root that gives AI tools a short, structured index of your most important pages. Read llms.txt explained for details.
Which LLMs matter most for brand visibility?
Those your buyers use. Digimetrics tracks GPT-4o, Claude, Gemini, Perplexity and Google AI Overview, which cover the main assistants and Google's own AI answers.
Find out what AI says about your brand.
Check five AI engines in one run: free for 7 days, no card.