These principles are in line with modern educational theories
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 commonly
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 ontologies
and authoring