I've posted a few entries in the past questioning the value of the Semantic Web as currently envisioned by the W3C along with its associated technologies like RDF and OWL. My most recent post about this was On Semantic Integration and XML. It seems I'm not the only XML geek who's been asking the same questions after taking a look at the Semantic Web landscape. Elliotte Rusty Harrold is at WWW2004 and wrote the following opinions of the Semantic Web on Day 4 of WWW2004
This conference is making me think a lot about the semantic web. I'm certainly learning more about the details (RDF, OWL etc.). However, I still don't see the point. For instance what does RDF bring to the party? The basic idea of RDF is that a collection of URIs forms a vocabulary. Different organizations and people define different vocabularies, and the URIs sort out whose name, date, title, etc. property you're using at any given time. Remind you of anything? It reminds me a lot of XML + namespaces. What exactly does RDF bring to the party? OWL (if I understand it) lets you connect different vocabularies. But so does XSLT. I guess the RDF model is a little simpler. It's all just triples, that can be automatically combined with other triples, and thereby inferences can be drawn. Does this actually produce anything useful, though? I don't see the killer app. Theoretically a lot of people are talking about combining RDF and ontologies from mulktiple sources too find knowledge that isn't obvious from any one source. However, no one's actually publishing their RDF. They're all transforming to HTML and publishing that.
I've written variations of the same theme over the past couple of months. It's just hard to point at any practical value that RDF/OWL/etc provide over XML/XSLT/etc for semantic integration.