Although "tagging" is often promented as an alternative to organization by a hierarchy of categories, more and more online resources seem to use a hybrid system, where items are organized into broad categories, with finer classification distinctions being
Smarking is a social bookmarks manager. * Save all your bookmarks online, ready to be accessed everywhere * Learn more about your favourite arguments * Make some of your bookmarks public, private or visibles only to your friends * T
New Ajax social bookmark URL(you can see with what tags one have bookmarked you) and tag search. Says it will be adding more social bookmarking query services almost daily.
B. Krause, R. Jäschke, A. Hotho, und G. Stumme. HT '08: Proceedings of the Nineteenth ACM Conference on Hypertext and Hypermedia, Seite 157-166. New York, NY, USA, ACM, (2008)