ECML PKDD Discovery Challenge 2008

This year, the ECML/PKDD's discovery challenge is set about social bookmarking. There are two main tasks: Spam Detection in Social Bookmarking Systems and Tag Recommendation in Social Bookmark Systems. This challenge is organized in conjunction with the Web 2.0 Mining workshop, and seems very interesting. Test data set will be released on July 30th, there is enough time to try something :)