The Resource Description Framework (RDF) is a W3C standard for talking about URIs in XML. It's also a cornerstone of the Semantic Web. More information is at the W3C's RDF web page.
A promising resource is the RDF Survey, filled with links on RDF. The most comprehensive however, is Dave Beckett's RDF Resource Guide which lists nearly everything.
If you want to get started writing RDF, there's John Cowan*'s Quick Start Guide: RDF Made Easy.
RDF defines an abstract way to describe just about anything. It does this by allowing you to make statements about resources. Resources are identified by a Uniform Resource Identifier (URI). The most common form of URI is a URL, like http://logicerror.com/. However, this does not mean that the resource must be accessible through the Internet; it only means that it must have an identifier.
Part of LogicError. Powered by Blogspace, an Aaron Swartz project. Email the webmaster with problems.