What happened? Groupon B&N brings up $10 for $20 and what not, surely they weren't stupid enough to have a 50% off coupon on one item or something like that?
Technically there was a limit of one groupon per person, however the system let you order multiples each
from multiple cities. Basically you "buy" a few from several cities tallying the total amount you were looking for.
The other caveat was that you also were "technically" not allowed to stack multiple groupons on an order. Early on, this wasn't a problem and B&N's online system processed orders with dozens of these codes (they were essentially B&N "e-Gift certificates"). Not long after B&N started getting hammered with these orders, they started limiting the online system to 3 of these per transaction, and also halting some of the big ticket orders pending fraud reviews - many of which ended up shipping anyway. There were some people who were spending thousands of dollars worth of groupons picking up multiple Nook Colors, video game systems, or other high value items.
Finally, many of the local stores had no problems accepting the groupons as well. I personally bought a Nook Color using 13 of these groupons in a store.
Needless to say, the coupons that groupon gives out are completely subsidized by the company that's offering them. There was an estimate that B&N ended up losing several million dollars because of the deal.
So basically that leaves us with Groupon's business model - I'm sure they get a cut of some "advertising" fee - but for the most part they're banking on big business using their service. After a couple of escapades like the B&N fiasco (and it wasn't the ONLY one either), it's why we're seeing really crappy regional groupon deals these days instead of good ones.