Purpose: An open-ended document/html page which that can be changed by wikispace members. Usually a wikispace has a dedicated topic of discussion or statements. The space can contain pictures, html and even blogs.
Use: I think that it would take a lot of time to monitor this type of everchanging document. If this was to be used in the classroom there would have to be plenty of time dedicated to etiquette. I find at the middle school level students will put other students down at a moments notice, this could be dangerous on the web. Although, there is an email notification setting you can use so you know when changes have been made.
It would be interesting to post a personal podcast and have a discussion about it. Getting insight on a project or idea from an outside person would be refreshing for the student.
Design: I have a hard time with the layout of the pages. I am sure there is some customization you can do, but overall it is set up the same way. Lots of text on a page, you have to search around for what you need/want.
Overall: I am undecided on if I would use this product in my classroom. Maybe after getting my curriculum solid I could incorporate it in as a why to document what we are doing. Then the students who has different jobs in my classroom could comment on the way they see other peoples jobs and such.