These principles are in line with modern educational the- ories such as constructivism and connectionism and thus make Web 2.0 applications very attractive for teachers and learners. Wikis, blogs, and social bookmarking are now com- monly used in learning [2]. Recent work at the crossroads of technology-enhanced learning (TEL) and Web research focuses on exploiting Web 2.0 features such as tags for user modeling [16], personalization of mashups [36], and ontolo- gies and authoring [1].