Samizdat
http://www.nongnu.org/samizdat/
Samizdat is a generic RDF-based engine for building collaboration and open publishing web sites. Samizdat builds its underlying data model on RDF (Resource Description Framework), and defines a schema of resource classes and properties for core concepts of a Samizdat site: member, message, thread, tag, proposition, vote, version, part, and so on (see Concepts document).