Enough already with this tagging frenzy! Tagging is a poor substitute for hierarchical folders. Tagging is for people who don't organize. Tagging is a way to improve searching, and search is what you do when you have lost something. If you organize, you don't have to search. There is nothing wrong with tagging - but it is not a way to organize.
I like Flickr and I like Gmail, but they don't let me organize. Sure, I have tagged my 5500+ photos, but they are all floating around there without structure.