What do Taco Bell, Dunkin’ Donuts, 7-Eleven. Quiznos and Red Robin have in common? Aside from serving up food items that may expand your waistline, they now offer virtual currency in the form of Facebook Credits just for making a purchase.

This new customer rewards program is the brainchild of startup company Plink, which, according to the website, is the “first-ever Facebook Credits-based loyalty program that rewards members with Facebook Credits for dining and shopping at their favorite restaurants and offline retailers.”

Risk: Credit Card Data Required

To use the program, new members create an account, then register a credit or debit card of their choice. Plink members then earn Facebook Credits by using their registered card when dining-out or shopping at participating restaurants and offline retailers.

Registering a credit or debit card requires that Plink be given access to sensitive bank account information. For users who are squeamish about risking such data, Plink ensures its security protocols are locked down tight. The site is verified by VeriSign and Truste and uses bank-level data encryption.

Reward: Convenience, Instant Credits, and Low-Cost

Once users register, any time they make a purchase at any of the participating retailers they earn instant Facebook Credits, which can be used to buy premium stuff on social games like Farmville, Cityville, TheSims, or any other game that accepts them.

An additional benefit, one that applies both to retailers and customers, is convenience. Customers no longer have to carry cards or keychain fobs, print out coupons, or use a code to get rewards. For retailers, the program requires no POS (Point-of-Sale) integration, paper coupons don’t have to be collected, or staff trained. There are no set-up fees, print costs or merchandise to purchase either. Participating retailers simply pay Plink a percentage of each sale that occurs from registered members.

Another benefit, especially to retailers, is the low-cost involved with using virtual currency. “The reason virtual currency microincentives work is because they are so cheap to distribute, and users perceive their value as higher than their cost,” said Techcrunch, which added, “Since it essentially costs nothing to drop Credits into someone’s Facebook account, businesses can cost-effectively reward users with just a few Credits, which typically cost $0.10 each.”

Social Games a Growth Industry

While I’ve never been a fan of social games, it is an industry that is experiencing phenomenal growth. A recent study from Juniper Research said that the amount of money being spent on virtual currency via in-game mobile apps will jump from $2.1 billion in 2011 to $4.8 billion by 2016.

This appears to be a win-win-win for all concerned. Customers are rewarded with Facebook Credits they can use on social games. In return, retailers are rewarded with greater loyalty from those customers. And, finally, Plink is rewarded with a portion of each transaction that results from this fast food meets Farmville love fest.

“Facebook Credits is the missing ingredient that’s been needed to connect social media to offline sales,” said Plink founder Pete Vogel. “Now with the ‘glue’ of Facebook Credits our national restaurant and offline retailer partners have a way to tap into the nearly 800 million users on Facebook, motivate them to become loyal customers, and reward them.”

Plink rewards restaurant customers with virtual Facebook Credits