I have already been using Wikis for a teacher inservice I have been teaching. I was a "self taught" wiki user and designed this wiki with my colleague
http://bagladies.pbwiki.com/We looked at pbwikis and wikispaces and decided to use pbwikis for ours. It is quite easy to set up a wiki and easy to inbed the links and videos. Students really like to edit wikis and especially like the widget that shows who is reading their wiki. What could be more motivating for a student than to see people from other countries reading their wikis?
I see the difference in a wiki or a blog- a blog is really only one person's thoughts and ideas but a wiki is an interactive tool where anyone can add and edit. Seems like a better tool....