Just a few days ago I revised an old social  friend named Foursquare.  I hadn’t been there for a while, as I am a digital nomad, often trying new tools to formulate an opinion, and then move on to a new toy as fast as they come unless they really offer something of value.  Lately I have been busy pinning images while watching the copy write storm brew.

By my real life friends have called me back to Foursquare through persistent invitations and check-ins. (It seems to have reached mainstream – perhaps a reason why it is no longer the little darling of the Digerati?) So off I went to reacquaint myself with the application.  This was on a Saturday morning that was devoted to mundane chores.  With my shopping bags forgotten (again) in the backseat of my car, I rolled into Wholefoods and remembered to “checkin.”  I was thrilled to learn that that my worldwide digital check-in made while perusing the cereal isle was rewarded with a discount.

In order to participate in the rewards program, I needed to link my AMEX to my Foursquare account and would subsequently see a $5.00 refund on my charge card bill.   While the act of submitting my credit card number to FourSquare did give me pause, it was the outstanding business model design that really stopped me in my tracks.

By motivating people through discounts and coupons, AMEX – in partnership with key vendors- has enabled a win-win situation that creates viral buzz for the vendor, enables AMEX to gather key data about consumer spending habits and whereabouts, while requiring them to increase their use of their card in places where people are less likely to charge. All this for the price of a digital check-in.

AMEX is also building business linkages on Twitter too. Today, GigaOM covered the AMEX / Twitter partnership in an article and explains how people can leverage the newly formed twitter account to enable people to tap into coupons, but I personally think the FourSquare program has a stronger approach.

Have you seen any remarkable or resilient social business models out there? What did you like about them? What actions did they inspire you to take outside of your norm, and why?