Bookicious - Find the best new book to read with books collections for makers, founders and entrepreneurs.
Goodreads - See what your friends are reading.
Riffle - Just good books and the readers who love them.
Bookcelerator - A curated directory of books that will make you smarter
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