Goodreads - See what your friends are reading.
On Deck - Business Loans | Small Business Funding | OnDeck
LibraryThing - A home for your books.
Readgeek - Your personal book recommendations
Meet New Books - Suggestions on books to read next. Find books that are similar to what you've read before. See what readers recommend. You can also search by trope or genre: romance books, fantasy books, paranormal books. Look for fiction or non-fiction, and more.
What Should I Read Next? - Book recommendations