I have a habit of checking out reviews on Goodreads. I don't take it too seriously, but the UI is less busy than Amazon and reviews are often a little more chaotic, random, and personal. I like that. I use it to track the books I read, which aren't many but it's simple enough. From my own sample, Goodreads rarely form my decision on which books to buy, but it's up there in my mental algorithm mixed with a bunch of other stuff.