Semantic Web
FOAF
FOAF (from "friend of a friend") is an RDF based schema to describe persons and their social network in a semantic way.
Last week, the W3C Provenance Working group released 13 documents simultaneously that together define a framework for interchanging provenance on the Web. We are really excited about this release as it a complete, full and stable definition of PROV and includes 4 Proposed Recommendations . While 13 documents is a lot, this is because we have broken down PROV into chunks designed for particular communities and usages.
Semantic Web - W3C
RDF Primer
The Resource Description Framework (RDF) is a language for representing information about resources in the World Wide Web. This Primer is designed to provide the reader with the basic knowledge required to effectively use RDF. It introduces the basic concepts of RDF and describes its XML syntax.
From Common Tag Common Tags are defined using RDFa, a standard format for expressing structured data within HTML.
Common Tag - QuickStart