Wikis seem to be central to the idea of the read-write web as there can be many contributors on a topic of interest to all. There seems to be more emphasis on the community than on the individual who began the wiki. There is a difference to sites such as social networking or social bookmarking where the centrality of the individual is more significant.
The applications of wikis seem to be enormous in an educational setting. I've just bought the book by Will Richardson on the use of blogs, wikis and podcasts in the classroom. I hope to find further inspiration and some more structured strategies there.
I can see that a wiki on reading from the collection of the school library, my workplace, would be a good place to begin, as that is certainly a shared activity.