is a vocabulary which provides a data model of >750 real world entities (“movie”, “person”, “restaurant” and their properties in the RDF language.

The site is run by a W3C Community Group which was initially started by major search engine vendors.

Use cases on Websites

Webmasters can add markup (i.e., instances of entities with actual properties provided) to the HTML of their website.

For example, the website listing job offers could include “JobPosting” markup.

Web crawlers, such as the ones of major search engines, can then process and present this data in a meaningful way. So called rich result snippets, displaying search engine results are often fueled by this kind of data. In the case of JobPosting, regular job search engines will typically also crawl this data and automatically add the offerings into their database.

According to itself, more than 10 million websites serve structured data based on the vocabulary. As an example, this includes many major news outlets, such as the New York Times (Example page source; search for “ld+json”). for Email for Email is applying the idea of for Websites to email content. See for Email for more details.