we should really stop thinking there is always a direct parallel between web and physical equivalent. On the surface they look alike but the reality is that they are fundamentally different in scale and personalization/targeting/tracking possibilities which makes the online case completely different than the physical case. I can see all the products at costco, I cannot see all products on amazon for example. Besides, costco is not a monopoly, and I can go to target or safeway if I want to...