Sharing documents on dropbox, asking questions via facebook, download some summaries via wiki.
All fun and games but these environments have a lot of problems and are not made for education.
A lot of irrelevant content can be found, not structured, without a lot of interaction and no or small validation of the quality.
And if you are really unlucky a co - student deletes a folder on dropbox during the exam period!
Creating an optimal study platform for interaction, sharing and working together!