Goodreads - See what your friends are reading.
LibraryThing - A home for your books.
What Should I Read Next? - Book recommendations
GoodBooks.io - Largest curated collection of 8,500+ book recommendations.
Bookicious - Find the best new book to read with books collections for makers, founders and entrepreneurs.
BiblioteQ - BiblioteQ strives to be a professional cataloging and library management suite. The SRU and Z39.