Journal of Information Science. we discovered regularities in user activity, tag frequencies, kinds of tags used, bursts of popularity in bookmarking and a remarkable stability in the relative proportions of tags within a given url.
BibSonomy is a system for sharing bookmarks and lists of literature. When discovering a bookmark or a publication on the web, you can store it on our server. You can add tags to your entry to retrieve it more easily. This is very similar to the bookmarks/
B. Krause, A. Hotho, and G. Stumme. Advances in Information Retrieval, 30th European Conference on IR Research, ECIR 2008, 4956, page 101-113. Springer, (2008)
A. Hotho, R. Jäschke, C. Schmitz, and G. Stumme. Proceedings of the 3rd European Semantic Web Conference, volume 4011 of LNCS, page 411-426. Budva, Montenegro, Springer, (June 2006)