It depends on the business type, but I'd suspect most business owners are savvy enough to know it won't help them acquire customers. I got a groupon to eat at a restaurant in Berekley, $10 for $25, and either the prices were specifically marked up to combat the groupon, or the owners are suffering some delusions of grandeur. Either way, the food was good, but it wasn't worth 40/person, and I won't go back.