Cool URIs for the Semantic Web

Members of the W3C Semantic Web Education and Outreach (SWEO) Interest
Group have published an Interest Group Note "Cool URIs for the Semantic
Web." It constitutes a tutorial explaining decisions of the Technical
Architecture Group (TAG) for newcomers to Semantic Web technologies. The
document was initially based on the DFKI Technical Memo TM-07-01, 'Cool
URIs for the Semantic Web' and was subsequently published as a W3C
Working draft in December 2007, and again in March 2008 by the Semantic
Web Education and Outreach (SWEO) Interest Group of the W3C, part of the
W3C Semantic Web Activity. The drafts were publicly reviewed, especially
by the TAG and the Semantic Web Deployment Group (SWD). Summary: The
Resource Description Framework RDF allows users to describe both Web
documents and concepts from the real world -- people, organisations,
topics, things -- in a computer-processable way. Publishing such
descriptions on the Web creates the Semantic Web. URIs (Uniform Resource
Identifiers) are very important, providing both the core of the framework
itself and the link between RDF and the Web. This document presents
guidelines for their effective use. It discusses two strategies, called
303 URIs and hash URIs. It gives pointers to several Web sites that use
these solutions, and briefly discusses why several other proposals have
problems. Given only a URI, machines and people should be able to retrieve
a description about the resource identified by the URI from the Web. Such
a look-up mechanism is important to establish shared understanding of
what a URI identifies. Machines should get RDF data and humans should get
a readable representation, such as HTML. The standard Web transfer protocol,
HTTP, should be used. There should be no confusion between identifiers
for Web documents and identifiers for other resources. URIs are meant
to identify only one of them, so one URI can't stand for both a Web
document and a real-world object.