Wikis Around The Classroom

I'm interested in the idea of using wikis as a way for students to build papers online from scratch and allow others in the class to edit them collectively. While I'm not a big fan of Wikipedia, wikis could be really useful for smaller groups to interact and share/contribute material. This would be an improvement over what I've done in past, which was to use discussion threads for students to post their material and get feedback. Here's an interesting article on using wikis in primary education. Anyone out there used wikis in the workplace or elsewhere, and if so, did you find them useful?