Here's an O'Reilly.net column by Andy Oran on The Semantic Web

The concept of the Semantic Web is that, using XML and other technologies, web creators can formally tag text and objects so that automated agents can help us deal with information overload.

But how do we make all that up-front tagging worthwhile? And can tagging, even if it's all done and done excellently, really provide the queues that we, the humans using the system, need?

What we really need is a system that understands how we track and sort and interpret and makes that process simpler and broader.