RAG (Retrieval-Augmented Generation)
Technique where an LLM first retrieves facts from an index, then generates the answer. Foundation of AI search.
Full definition
RAG (Retrieval-Augmented Generation) is an LLM technique where the model first retrieves relevant facts from an index or knowledge base, then generates an answer based on them.
- •Unlike "pure" LLM calls (where the model answers only from its parameters), RAG allows:
- •Access to current information (news, prices, documents)
- •Reduced hallucinations — answers are grounded in specific sources
- •Source citation — users can verify facts
Where RAG is used in search
- •RAG powers all modern AI search engines:
- •Perplexity — RAG as the core mechanism
- •ChatGPT Search — RAG over the Bing index
- •Google AI Overview — RAG over Google's own index
- •Bing Copilot — RAG in the Microsoft stack
All of them follow: user query → retrieve top-N documents → pass documents to LLM with instructions like "answer using these sources".
What it means for SEO
Since RAG systems cite specific sources, your content must be "extractable": structured, with direct answers in opening paragraphs, with proper schema markup. This is the essence of GEO optimization.