In this website you can find information about folksonomies, their strenghts and weaknesses, and Sem4Tags an approach to improve multilingual folksonomies using semantic web techniques. In addition, there is information about the developed demo software to associate tags with semantic entities.
P. Mika. Proceedings of the 4th International Semantic Web Conference, Volume 3729 von Lecture Notes in Computer Science, Seite 522-536. Springer, (2005)