Understanding it
Each block on the SERP reflects how Google reads the query. A map pack signals a local search, product listings signal purchase intent, an AI Overview signals a question that calls for a summary. The layout of the page tells you what Google thinks the searcher wants.
That is why an SEO looks at the SERP before writing anything. If the top 10 results are store category pages, a blog post will struggle to break in, however good it is. If they are guides, a product page will be off target.
Ranking alone no longer measures visibility. Ranking 1st below an AI Overview, 4 ads and a map pack is not worth the same as ranking 1st on a page of plain links.
A concrete example
Illustrative example: two neighboring queries
An accounting firm targets “accountant Lyon” and “how to choose an accountant”. The first SERP shows a map pack with business profiles, then directories. The second shows an AI Overview and guides.
The firm takes away two separate projects: its business profile and a local page for the first query, a complete, well-structured guide for the second. A single page for both would have missed both.
The common mistake
Tracking a ranking without looking at the page
A report that says “position 3” tells you nothing about what sits above it. Look at the actual SERP, on mobile, for your key queries, at regular intervals: it shows how much visibility a ranking really delivers.