RDF, OWL, SPARQL, and now SKOS, the Simple Knowledge Organization System Reference. "Using SKOS, conceptual resources can be identified using URIs, labeled with lexical strings in one or more natural languages, documented with various types of note, linked to each other and organized into informal hierarchies and association networks, aggregated into concept schemes, and mapped to conceptual resources in other schemes. In addition, labels can be related to each other, and conceptual resources can be grouped into labeled and/or ordered collections." How many of these things do we need before the Semantic Web is here? I think Clay Shirky was right: it really is turtles all the way up. The Semantic Web is like an undergraduate paper: never really completed, just abandoned at the point of exhaustion.
