Ah, wikis. They make me think of Chewbacca the Wookie.
The Book Lovers Wiki by the Princeton Public Library is one that I find could be very interesting and useful, although on a personal level, I would love to see some teen reads. Go Librarian Chick wiki! Thanks for giving some love to young adult literature.
I've found wikis about library conferences uber useful. I was able to find a roommate that way, so rock on. What a way to take the edge out of planning for a conference trip. :D