GLOSSARY
Structured data
Structured data is markup added to a page's code, usually in JSON-LD format, that explicitly tells search engines and AI assistants what a piece of content actually is: a product, a review, a FAQ, an organisation, rather than leaving them to guess from the visible text alone.
Why it matters
It is what produces rich results in search, star ratings, FAQ dropdowns, breadcrumb trails, and it is increasingly how AI assistants extract a clean, unambiguous fact from a page rather than having to parse and interpret prose. A page with accurate structured data is easier for a machine to quote correctly. It also compounds over time: a site with consistently accurate structured data across many pages builds a pattern search engines and AI systems learn to trust, extracting facts from it more confidently than from a site with none. It also helps a business appear correctly in knowledge panels and voice search results, where the underlying answer is drawn from structured facts rather than free-form page text.
What goes wrong when it's handled badly
Structured data has to match the visible content on the page exactly; marking up a FAQ or a price that is not actually shown to visitors is treated as manipulative by search engines and can trigger a manual penalty. Copy-pasting a schema template without updating every field to match the actual page is a common, easily caught mistake. A concrete example is a product page marked up with a five-star aggregate rating in its schema while the visible page shows no reviews at all, a mismatch search engines actively check for and penalise once detected. Validating markup with a testing tool before publishing, rather than assuming a template is correct because it was copied from documentation, catches most of these mismatches before they reach a live page. Re-validating markup after any redesign, not only when it is first added, is what catches drift as a page's visible content changes over time.