I used Restaurant.com 'certificates' three times. First time, all was perfect and I didn't even meet the minimum. Second time, the food was awful and overpriced (i. E. no savings.) Third time, the creep at the counter tells me Restaurant.com just took their logo and started selling coupons without telling them. Yeah... sure. If they take your coupon and the food's good, that's fine. Don't expect that happen all or even MOST of the time.
One more thing, I love the boring schlemiels who sit there with a calculator and buy exactly $20 worth of food. I mean a lot of these restaurants are struggling as it. What losers.