This article introduces core Semantic Web concepts and standards, and explains how to expose an LDAP directory as a service that Semantic Web applications can consume using the open source SquirrelRDF utility.
This is the the Annozilla project, designed to view and create annotations associated with a web page, as defined by the W3C Annotea project. The idea is to store annotations as RDF on a server, using XPointer to identify the region of the document being annotated.