It's not a novel idea, RewardsNetwork awards miles for dining with merchants they have signed up http://skymiles.rewardsnetwork.com/

UPromise has had a similar program tracking not just restaurants, but all sorts of shopping venues http://www.upromise.com/welcome

American Express will also track your Amex purchases and assign loyalty rewards based on their Link, Like, Love Facebook promotion https://www.facebook.com/americanexpress

Are you not okay with an idea? Or not okay with Groupon, Inc. being another company to implement this fairly commoditized loyalty program?