Practical Metadata

Don't walk, run over to pandora.com for a glimpse at a robust music ontology in action! This website is a recommender system that uses a music ontology (smartly called the Music Genome Project) to recommend music similar to your known favorites by decomposing your preference into its component parts. I have been using this for a few days and my initial impression is that it works great! Kudos!
How many more "Genome" (i.e. Semantic Web) projects will we see in the coming years? If this is any indication, my guess is many, many ...