[Groxx]

So... the cafe was stupid, and nearly destroyed themselves because of it.

Capitalism / evolution says they had it coming. Yes, Groupon certainly took the assholish route, but taking advantage of stupidity is within their rights, and even within expected behavior in a marketplace.

FYI for future sales through any intermediary: know your terms. If they charge $X, and you want to sell something for $X, don't do it because you'll be left with $0 (unless that's what you want). If you might not be able to handle above a certain volume of takers, restrict the number of sales.