Does Free Food Gain Long-term Customers?

Mars Inc's Chocolate Relief Act/ Website

Promotions of free food have really caught on during this recession. Like a number of restaurant franchise chains of late, such as Quiznos and KFC, here is yet another example of a consumer food company giving away free product via Internet coupons. This one from Mars Incorporated.

Mars Real Chocolate Relief Act

By this point, the free food bit is getting a bit old. People will still wait in line for a freebie, but is a copycat promotion really effective in the long term??