I think it is interesting that some people cherish the Amazon recommendations above everything, whereas others are fundamentally unhappy with it. Unfortunately I belong in the later category. Sure, sometimes Amazon comes up with something interesting to me, but in general it does not. I wonder if I am just too weird for a recommender system to grasp, or if it hints at the system still being very imperfect.
Great article. Generalized personalization is going to be an increasingly big deal. In a few years, I think it'll be expected that almost any site you visit already knows who you are and what you're like.