Demaestro - 4:18 am on Dec 10, 2010 (gmt 0)
A $100 service becomes $25 for the merchant as it needs to be at about 50% discount and Groupon gets a cut. That's not sustainable for obvious reasons.
Maybe not the narrow use-case that you outlined but in the real world this is a great service.
Think of businesses with fixed expenses. Like a Rock Climbing room.... it doesn't matter how many people come through the door the rent, the utils and the staff is the same price.
If you can get a bunch more people in the door even at 10% that is a good thing... This and many other scenarios are why it will be around for a long time to come.