edutagger is a social bookmarking service for K-12 learners and educators, allowing you to store your web links online and share them with others, all within an educational context.
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.
A. Hotho, R. Jäschke, C. Schmitz, и G. Stumme. Proceedings of the Conceptual Structure Tool Interoperability Workshop at the 14th International Conference on Conceptual Structures, стр. 87-102. (2006)