[wutbrodo]

This is particularly true for businesses that offer things like yoga classes, for whom the marginal cost is ~0. This is obvious to everyone now, but early on most small businesses didn't think of Groupon as what it is: a form of marketing that requires a fairly particular cost structure to be cost-effective.

[davemel37]

I did an analysis of the best deals in the early days of Groupon, and they were all classes that were better when attended with friends. (I think the best selling one in the early days was a cupcake baking class.)