"The Semantic Web Community Portal" - i.e. a site that I should spend some serious time reading and following the links from, not specifically because my current software is "Semantic Web" but because so many people I know are working in this area, the site would help me understand what they are working on significently better.
As well it appears to be a well organized and thought out site (which you would hope it would be given the topic, but you never know).
I think there is some overlap between the Semantic Web and my MeshForum conference, though clearly the two topics are not completely related either. SemanticWeb is very much more of a technical challenge and problem while MeshForum is more about (I hope) theory and practice, and the theory in question covers much more then just computer programming.