While there is a lot of research and implementation of techniques of semantic integration of metadata stored in relational databases used by performance management vendors (e.g. CWM, or the Common Warehouse Metamodel), there is definitely a renewed interest in standards-based metadata representations of web content, leading to the "semantic web". Naveen Balani presents a very thorough overview of the semantic web that is well worth reading in his article on IBM's Developer Works entitled, "The future of the Web is Semantic".
The Semantic Web provides a common framework that allows data to be shared and reused across application, enterprise, and community boundaries. You can think of the Semantic Web as an efficient way to represent data on the World Wide Web, or as a database that is globally linked, in a manner understandable by machines, to the content of documents on the Web. Semantic technologies represent meaning using ontologies and provide reasoning through the relationships, rules, logic, and conditions represented in those ontologies.