Goodreads - See what your friends are reading.
GoodBooks.io - Largest curated collection of 8,500+ book recommendations.
LibraryThing - A home for your books.
BookAuthority - BookAuthority collects the most recommended books on business, technology and science - as featured on CNN, Inc and Forbes
What Should I Read Next? - Book recommendations
TBR: Book List Tracker - TBR is a simple, elegant and modern place to track your reading.