I find it amazing how lousy Amazon's site is considering how long it's been around and how rich a company they must be. The search function is crap, the options for filtering and ordering results are inadaquate, and many, many products across different categories don't tell you crucial information (not that anyone but me ever buys cds any more, but again and again Amazon won't tell you the track-listing, to take but one example).
And, yeah, they also mix up user reviews for different products (ones which Amazon decides are 'similar' but which in reality are not at all).
Ebay's not a lot better. I don't quite understand why competition doesn't oblige both of them to improve their websites. I guess website design is not a critical part of why they dominate.