This is kind of old news, but I wanted to include a link to the New York Times article that made me realize that Semantic Technology is on the verge of breaking through.  I especially like this bit:

“In its current state, the Web is often described as being in the Lego phase, with all of its different parts capable of connecting to one another. Those who envision the next phase, Web 3.0, see it as an era when machines will start to do seemingly intelligent things.”