Well, sure, I would never argue that you can't differentially price socks in different market segments, using coupons and regions and so forth. You obviously ca

Well, sure, I would never argue that you can't differentially price socks in different market segments, using coupons and regions and so forth. You obviously can, and everyone does, to some degree. But this hardly rises to the level of an incipient retail apocalypse. It isn't even new. This is nineteenth-century stuff. The question is: Will differential pricing be pushed farther, now that computers are available to dynamically segment the sock market in real time? (Perhaps wool socks will cost more depending on the current local wind chill factor?) Probably. But there's a real cost in trust and goodwill and complexity that must be balanced against the advantages of differential pricing. In general, customers don't love being segmented, particularly in ways that aren't long-standing traditions (as clippable coupons are) or that don't fall along culturally accepted lines (we'll pay more for goods with famous people's names on them, or with made in the USA labels on them - these are just and proper activities in American culture - but we will be less pleased to pay significantly more for goods at 4pm than we do at noon, or to pay more if we're a woman than if we're a man). And so customers will tolerate only so much market segmentation before they start looking for cheaper or more transparent alternatives: Join Costco, shop Priceline, bid for the goods on eBay from a grey-market reseller, use your wife's Amazon account instead of your own, make up some fake demographic information, whatever. And my hypothesis is that, if you think about pricing from the perspective of the airline industry, you're going to overestimate customer tolerance for fancy pricing games, because the airline-ticket market is constrained in unique ways that don't apply to other industries.