Huh. Like aliseadae I mostly do not browse books online--if I find something about a new book by an author I like, it's likely through LJ or my other online reading. Amazon recommendations are, to me, mostly just that it tells me a couple of books I've read already when I'm looking something up on their website.

So it is really interesting to hear how they can be used constructively--I won't start right this moment, since I'd probably have to input a lot of stuff at the beginning to make it give me interesting suggestions, but I will definitely think about it.