i have bought coupons from them for a couple of restaurants in our area. (there aren't very many) we've had no problem using them. there is a limit of one per restaurant per month. used to get them from ebay but don't know if they are still doing that and with coupons codes it is often cheaper to get them from the site. read the individal restrictions before you purchase, each restaurant is a little different...must have party of 4, one per table, during lunch hours only, those type of things...
these are often a GREAT deal!
our favorite was the 50% off,limit 8 persons that we have used several times for family dinners at a local mexican food place. have bought for $1, 1.50, and $3, what a deal!