Don't get me started on Eduzendium.
Actually I think we should so it can be improved in the future. Who knows I might let my students in here for a free for all.

I think one lesson of interest here is that although all students are very computer savvy they can also be pretty useless if the site or project holds little interest for them. Another issue is the lack of dialog/interaction. Possibly the students do not even know the talk page exists.
I have seen the same in a small seminar series I have been involved in this semester too, which, in theory, is all about dialog. This class was about writing and presenting poster at a conference (in this case the undergraduate research symposium). While the students do the work and upload very good posters they are less good at providing feedback for their peers or responding to feedback about their own poster. I have come to the conclusion that they just see the wiki as a depository rather than a forum for discussion.