Goodreads - See what your friends are reading.
01WebDirectory - A general web directory that lists business and informative websites under various categories for...
BookWyrm - Social Reading and Reviewing
DMOZ - DMOZ is a multilingual open-content directory of World Wide Web links.
LibraryThing - A home for your books.
Curlie Directory - Curlie is the largest human-edited directory of the Web.