Schema.org
Schema.org is a collaborative project started in 2011 by Google, Microsoft, Yahoo and Yandex to create a common vocabulary of tags that webmasters can use to mark up their content so that search engines can understand it better.
Its goal is precisely to help make document codes more readable and meaningful to both humans and machines.
Concretely, it has led to the development of structured data, which is precisely a common, participatory vocabulary – named Schema.org, in fact – based on Microdata, RDFa or JSON-LD formats to enable Web pages to mark up their published content autonomously via metadata.
Schema.org markups are very numerous and include, for example, information about ratings, reviews, e-Commerce products, events, and more; by using them appropriately, we can improve the way websites appear in search results, because Google (and other search engines) make use of such microdata to compose certain features of their SERPs, directly showing items such as starred reviews, images, and opening hours in so-called rich results.
