The current hype about the Semantic Web is crap. The idea of knowledge theory and all that crap is great, but I think that it's major overkill that you can't bootstrap against. I think that as a result, a huge huge number of the examples and so on out there are really crap.
However, I think that the technology is good. I think the underlying idea is good. And I think that once you get a significant chunk of the data out there into RDF, it's a hell of a lot easier to deal with and repurpose than other things. I can run queries against it. I can do all kinds of funky things against it. The world is my database.
Some people will say that looking at the semantic web this way is a bad way: you're avoiding the whole "machine readable and understandable" step that is considered a major part of the tools. You're ignoring the fact that this is designed for robots to read and understand and make deductions from, and all those fun and wonderful things. But to be honest, I've never seen those fun and wonderful things work well. What I have seen work well is RDF as a data interchange format. In the same way that RSS works relatively well at describing site content, RDF can work well at describing almost any content with relatively small amounts of work.
I've seen nifty tools be built out of the semantic web. The ability to see pictures of people who are in an IRC channel isn't much, but to be able to click through and see the other information is cooler. To use the FOAF explorer to click through and see things these people may have worked on is cool. To describe who I've met, and run a path from me to someone else using only a specific set of relationships is cool. Yes, they're geeky-cool, but to me, geeky-cool is all that matters.
There's also the fact that RDF and similar technologies can do things with the data that you wouldn't be able to do otherwise. Display a picture alongside a name of a developer for a project described in DOAP via their FOAF file. Show content from their homepage, described in RSS. Show a bunch of different otherwise disparate chunks of information together, in a way that they are more useful.
That's what I think RDF and the Semantic Web are good for, at the moment. Eventually it may be something more impressive, but I don't care about that. I'm a hacker, I care about the now, and the now is nifty data integration. I believe that's a use of the semweb that can't be denied, and I think it's pretty nifty, if not absolutely neccesary.