You Down with Folksonomy?
Gene supplies a good overview of Folksonomy, which is the bottom-up social classification that takes place on Flickr, del.icio.us, etc. It would be great to have a tool that could help organizations develop a folksonomy over time. Gmail from Google could develop a great folksonomy that could be overlaid on ones own searches.
Marry this idea with Paul Ford's "Google beats Amazon and eBay at Semantic Web" and you have a wonderful jump on the Semantic Web that is personalized. Take Gene's idea of building a thesaurus or crosswalk of terms within and across systems and things can really take off. There would need to be contextual tools added to handle the multiple definitions like Macintosh is a synonym for Mac, but Macintosh is an artist and a computer, while Mac is a computer, artist, and British term for raincoat (short for Macintosh). Hence the Semantic Web adds context to get these things straight.