Bookcelerator - A curated directory of books that will make you smarter
Goodreads - See what your friends are reading.
Four Hour Book Club - 300+ Books recommended on the Tim Ferriss Show 📚
LibraryThing - A home for your books.
Booknshelf - Social book and bookshelf discovery platform.
BookAuthority - BookAuthority collects the most recommended books on business, technology and science - as featured on CNN, Inc and Forbes