I started poking around with Drupal's RDF module last night and ended up staying up VERY late. RDF is one of the languages supporting the semantic web and the semantic web may be, or already is depending on your view, the next great thing on the Internet. The idea of the semantic web is to leverage all the content on the web as structured, meaningful data. This would enable automated systems to search and process this data with reference to its meaning rather than just a mass of unstructured text.

When last I looked at what was going on with the semantic web a few years ago, there were not many tools to work with. There are some very good tools now available. For example:

Drupal RDF

Yahoo SearchMonkey

MIT SIMILE

DBpedia

I'll have to make time to play more with this!