I have been using wikipedia.com for several years for information on pop culture items, etc. I explored several of the wiki tutorials and found out a lot of information about their setup that I didn't know. One site had a great suggestion to connect people who are on a waiting list for a popular book so that they can talk to each about that title.
I also explored the BookLovers Wiki of the Princeton Public Library. I like how it's just a simple website with brief reviews of all kinds of books. Customers send in their thoughts and give books the number of stars the book deserves. I also like how the site has pictures of the books' covers and a link to the library's catalog to see if a copy is on the shelf. We have something similar at PGCMLS' catalog website but it is links to book reviews from publishing magazines. It might be good to add a customer review feature to our website.