whatshouldireadnext.com

Website that performs the simple function of recommending books to you after you type in the name of a book you have already read. Obviously, it helps if the book is one you like, unless you want to get a list of books to be avoided.
Good potential here, but needs more individuals to give recommendations to make it a more comprehensive site. Of course, Amazon does something similar, but assuming you buy books for other people, that site is based more on buying rather than liking particular books.