WSJ has an interesting article about LibraryThing.com, a site that lets you create a database of your books, rate them, review them, and look at the catalogs of other users. The social information compiled by LibraryThing lets you find recommended books, the top-rated authors.

LibraryThing is free for users who catalog 200 or fewer books; after that it’s $10 a year or $25 for life.

Social Library Catalog at LibraryThing source