Over the past two years, I've seen several of these pay-less-than-the-full-value-of-the-certificate deals for restaurants. I never tried any of them because they were generally for establishments that were a considerable drive from our house, and, ah, tended to be the tier of restaurants that might be fine for neighborhood dining, but didn't merit a special trip.
Well, I just found
Half Off Depot for Atlanta, GA. This is the first site of its type that might be worth the investment: Jolie Kobe, Fritti, Meskerem, Bhojanic (!), and Cafe Intermezzo are just some of the restaurants available.
If I'm planning an outing with friends in advance (do I have any other sort of outing? :) ), it might be worthwhile to decide on the restaurant and buy one of these certificates.
Food for thought, as it were. Have any of you used this sort of discount? If so, what did you think?