Negative feedback worth less?

Wayne at Sellathon pointed me to an interesting phenomenon he's noticing. People online are starting to discount negative feedback. He points us to eBay Member Profile for totalcampus.com and also to book reviews on Amazon where positive reviews are marked "helpful" nearly twice as often as negative ones (at least in his research). In both cases, you've got people saying "stay away!" and still, others buy.

I think the reason is classic cognitive dissonance. For unrelated reasons, you've already decided to buy. Now, the negative feedback needs to be ignored in order to validate your earlier hunch that you wanted to buy.