GoodBooks.io - Largest curated collection of 8,500+ book recommendations.
Readwise - Effortlessly rediscover and organize your Kindle highlights
Goodreads - See what your friends are reading.
Clippings.io - Organize the notes you make on your Kindle
Bookicious - Find the best new book to read with books collections for makers, founders and entrepreneurs.
Klib - Kindle & iBooks Highlights Manager