Why it matters to a buyer
Schema markup makes a page eligible for some rich results, such as product prices, review stars and breadcrumbs, which can make a listing stand out. It also helps search engines connect your organisation, people and services into one consistent entity. For a buyer, the caution is that markup does not guarantee any feature and several rich results have been retired, including the FAQ rich result, so the reason for each type of markup should be stated rather than assumed.
How it is measured or applied
It is applied by adding a JSON-LD script to the page describing the organisation, the page, and the specific thing on it, such as a product, article or service, with values that match what the page visibly says. Markup that describes content not on the page breaks Google's guidelines. It is checked with Google's Rich Results Test and the Schema Markup Validator, and monitored in Search Console's enhancement reports, which show valid items, warnings and errors across the site.
Sources
- Introduction to structured data markup in Google Search, Google Search Central
