Have you checked out Library Thing yet? It's at www.librarything.com.
It's fascinating. I spent last night and this morning putting up most of the books I've read this year. It's a way to catalog your personal library or keep track of books you've read. It's also the hot social network out there for people who like to read. You can contact other people who read the same books you do, and find out what else they like.
I like it because I can see my entire "library" by book cover. I can also link directly from the book reviews here to that site, so I don't have to copy them or write a second review. (Thank you AdeptMagic.) And, of course, there's the opportunity to network.
Just what I need. Another fun website.