We've had quite a few people defend them on previous threads about groupon with really positive experiences.
They have tended to be places like paintballing or sky diving, things where the cost doesn't go up that much more with the more people who come. And who can upsell (paintballs, photographs). There's a technical business term for those businesses that I can't remember.
Service-oriented businesses tend to have positive experiences. Pretty much anything where you may have somebody sitting around 1/2 their time doing nothing, just to make sure you've got coverage during all of business hours. Any money you recoup from that 1/2 of the time is money in your pocket.
Anything with inventory costs (e.g. restaurants) have a much harder time. Food costs are a significant portion of the cost of serving a table. It wouldn't be bad to have a loss-leader for one or two meals, but grouponers don't become "the next repeat customer", so you just lose money on the meals with not much to show.
They have tended to be places like paintballing or sky diving, things where the cost doesn't go up that much more with the more people who come. And who can upsell (paintballs, photographs). There's a technical business term for those businesses that I can't remember.
But apparently they do do well out of groupon.