There is a new site called "Library Thing" that allows you to creat an account. Email not required for once. On this account you can post books that you read or that relate to a topic you are interested in. He is my list. http://www.librarything.com/profile/MJPage
This site may have some possiblities for use in reading circles or the classroom to help engage student in reading and discussion about books. Some of the features include groups, talk, chat and local map and events. check it out.