Schema.org

This refers to a collection of schemas, i.e., html tags, that webmasters can use to markup their pages in ways recognized by major search providers. Search engines including Bing, Google, Yahoo! and Yandex rely on this markup to improve the display of search results, making it easier for people to find the right web pages.

see:

• http://schema.org
• discussion of schema.org by Dr. R V Guha and Dan Brickley on the Ontolog Forum - ConferenceCall_2011_12_01