Making Student Blogs & Wikis Meaningful

We are experimenting with collaborative note-taking. Currently, a few students take notes during history class using Google Docs. At the end of the day, the notes are transferred to a wiki. We are thinking about creating other roles including: editors to edit the wiki, inquirers who create potential test questions from the wiki, and researchers to add relevant content to the notes via web surfing.

I think that it is working well so far. One question has come up. How do we make sure that all students are using the notes effectively? Most students take their own notes during class or synthesize the notes from the class wiki. HOW CAN I MAKE SURE THAT STUDENTS ARE AT LEAST SPENDING A FEW MINUTES EACH NIGHT REVIEWING THE WIKI? I thought about having them submit test questions. My worry is that they may just read the first few notes and not spend meaningful time reviewing all of the notes. We also thought about each student having their own blog.

Thanks in advance for any ideas!