Understanding it
A search engine reads a page’s text and infers a lot, but with a margin of error. Structured data removes the ambiguity: this is a price, this is a rating, this is the author. Google recommends the JSON-LD format, a block of code kept separate from the visible content.
Its best-known effect is a rich result: review stars, price and availability, an event date. Google decides case by case and has narrowed some types: since August 2023, FAQ rich results are reserved for well-known government and health sites.
Practitioners report that clean markup also helps language models read a page without mistakes. It does not replace the content, it makes it easier to extract.
A concrete example
Illustrative example: a training provider’s course pages
A training provider lists its sessions with dates, locations and prices in plain text. Google shows basic results, and the dates are sometimes picked up wrongly.
Each course page gets markup describing the course, the provider, the sessions and the price, checked with Google’s Rich Results Test. The key details become readable without interpretation, by Google and by the assistants that consult them.
The common mistake
Marking up what is not visible
Declaring reviews, a rating or an FAQ that do not appear on the page breaks Google’s guidelines and can lead to a manual action. Markup must describe what the visitor sees, nothing more, and be kept up to date when the page changes.