Schema.org

Schema.org

Schema.org provides a collection of microdata schemas, i.e. html tags, that webmasters can add to their pages to describe the things their pages are about. Getting Started provides a tutorial.

The articles Structured Web Gets Massive Boost and Schema.org - Threat or Opportunity? both provide good overviews on how Microdata and Schema.org relate to RDF, Linked Data and the Semantic Web.