This is not specifically an argument against Groupon, but with occasional discounting in general, such as seasonal sales. Economists, marketers, and business strategists have studied and argued about this for decades.<p>So, some businesses avoid discounts, and others embrace them. It probably depends a lot on the type of business whether they're a net positive or net negative; otherwise either the "sales are bad" or "sales are good" argument would have definitively won out by now as accepted wisdom.<p>Small businesses are often unsophisticated in their marketing, so Groupon probably benefits from some businesses not realizing discounts hurt their exact business, or overpaying for Groupon promotions. (Similarly, Google benefits from small businesses that sometimes overbid on AdWords/AdSense without rigorous ROI calculations, or fail to adjust their campaigns to eliminate negative-ROI outlets.)<p>But other businesses -- those that get a large benefit from awareness, and some number of new recurring full-price customers -- surely benefit. There will be some optimal frequency of promotions, to minimize their cannibalization of normal demand at full price. (Ideally, you'd want to offer the promotion only to new customers, but that would require some information-discrimination that's hard on the net, with promotions that are meant to spread like gossip.)<p>Groupon will be in a very interesting position, as they collect data on what works for different businesses and what customers respond to. They could tempt more businesses to overpromote, or help unsophisticated small businesses schedule optimal promotions. They could possibly deemphasize certain promotions to repeat customers, or emphasize them to proven customers of competitors.