Our solution is based on social bookmarking. Not surprisingly, we found that in their daily routine, lecturers search the Web for resources they can use in their lectures and mark them with bookmarks. While standard bookmarks are stored locally and hence only available for a single user and not reusable by other users, social bookmarking allows storing bookmarks on a server, accessible by other users and additionally annotated with user-defined tags. We therefore encouraged the lecturers to use social bookmarking service to store their bookmarks. Additionally, we instructed the lecturers to use a mixture of user-defined and predefined tags (in contrast to purely user-defined approaches as described in [2])