Web 2.0 tools for teaching and learning/Wikis

What are some possible applications of wikis in teaching and learning?

Discussion

 * Wikis are moderating systems that help diverse viewpoints to achieve consensus. ~Drew
 * I think sharing ideas and actually feeling like you have created something can be good for training sessions. ~Ashley
 * Wiki creation requires motivation, honestly. Unmotivated underclassmen won't make wiki material. ~Thia