Bart Deleye pointed me to this nice site called Shelfari. This site allows you to share the books you've read, the books you liked, ratings, reviews, ...
I know this has been done before. I just liked the application's smoothness. Visit shelfari and tell me if you liked it. My bookshelf can be found here: http://www.shelfari.com/o1518045977
I also have this bookshelf widget on the side of my blog.