How I Use It
I do not teach a class. I do, however, do collaborative work with a geographically disparate group on a resource guide project, for which this will work nicely. The idea of using a wiki as a collaborative space is (I believe) largely untested in a school setting, but I can see value in using it for collaboratvie learning projects, or even collaborative creative writing.
It's not a perfect system. When you go to a page, there are icons for the various functions (Page, File, Discuss, Project, Event), but they aren't labeled until you click on one of them. That's an unfortunate oversight on their part. Also, because it's not specifically intended for educational use, there's a certain amount of expectation of ability. It's easy to use, but it's not user-proof. As such, it would likely be appropriate for middle-school and above.