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, и G. Stumme. HT '08: Proceedings of the Nineteenth ACM Conference on Hypertext and Hypermedia, стр. 157-166. New York, NY, USA, ACM, (2008)
B. Krause, A. Hotho, и G. Stumme. Advances in Information Retrieval, 30th European Conference on IR Research, ECIR 2008, 4956, стр. 101-113. Springer, (2008)