One of the reasons that the merchants can offer lower prices via these services is that the prices will not appear in Google searches and therefore difficult to include in comparison shopping systems.Unless you’re Google, efficient pricing is the antithesis of profit. Instant, free, ubiquitous, constant, direct comparisons to the competition drives prices towards marginal cost i.e. profit = zero quickly. To escape this race to the bottom, information inefficiency must exist. Before the internet became ubiquitous, information inefficiency was the natural state in which society existed. Now it must be manufactured.

via Scott Rafer’s Blog : Gilt Groupe, Groupon, and avoiding SEO.