I think there is a distinction here between "groupon customer" and "business customer" highlighted in that comment that goes beyond the term "bargain hunter". You can still have bargain hunters that would only come to your shop once you display 10% off or once you're selling out stock that did not go away, but they still bring value to your business. That's different than a situation where neverending stream of discounts means you can change your provider as long as you're loyal to groupon.
That might be just word semantics that I'm missing, but I think there is a major distinction.
fijal is correct that I meant something much more fundamental than the bargain hunter problem.
Groupon's core selling proposition to businesses is that it will bring them people who can be cultivated into loyal, long-term customers. However, it's something of a fallacy because those customers are loyal primarily to Groupon. In fact, Groupon is actually a hyper-competitor to its business customers.
It's not just semantics or an issue of bargain-hunting. The model itself actively works against the core promise it offers to businesses.
BTW, while I'm not much of a Groupon fan, as a fellow-CEO whose tried something new and taken a lot of flack for it, I'll offer a little unsolicited advice: Don't let 'em get you down.
That might be just word semantics that I'm missing, but I think there is a major distinction.