Goodreads - See what your friends are reading.
BookWyrm - Social Reading and Reviewing
Readernaut - We are a small community of readers, sharing our adventures and supporting each other as we persue a life of learning.
BookAuthority - BookAuthority collects the most recommended books on business, technology and science - as featured on CNN, Inc and Forbes
LibraryThing - A home for your books.
Sebangsa - Social and mobile platform developed and designed for Indonesian users.