Schema is a common set of identifiers (schemas) to help flag the various “entities” on a web page. This effort to structure Web data allows web developers to assign specific HTML tags to all types of things like products, recipes, reviews, locations, etc. and was agreed to 3 years ago by Google, Microsoft, Yahoo, and Yandex. The idea being that properly tagged things would make it uniform and easier for search engines to understand, index and rank a page. While this concept was launched in 2011, a new study finds only 0.3% of the hundreds of websites tested have schema integrated.
So does it help with rankings? Read the story here.