What it is
A model trained months ago does not know today's facts, and it does not know your site. RAG fixes that. The system retrieves relevant documents in the moment, then writes its answer using what it just pulled. It is the bridge between a static model and live, specific information.
Why it matters
RAG is the reason on-page optimization still matters in the AI era. If your content is structured so a retrieval step can find and trust it, you get pulled into answers. If it is messy or buried, the retriever skips you. Understanding RAG explains why AEO and AI SEO work: they make your pages easy to retrieve and quote.
What to do
Make each page easy to retrieve in pieces: clear sections, descriptive headings, self-contained answers, and clean schema. The easier a passage is to lift on its own, the more likely a RAG system surfaces it.