Kevin: Domino's UK says that its social media campaign using Facebook and Foursquare was key in driving profits 29% higher. On Foursquare, they have what they call a superfans programme. CEO Chris Moore said that the "web-based activities offer a dual benefit of driving pizza sales online and building customer loyalty."
Kevin: With a spend of only $1000, McDonald's in the US says that a Foursquare campaign was able to increase foot traffic to its stores by 33%. They didn't measure increased sales, only traffic, however, there are other examples that did measure sales, such as Domino's UK that attributed its social media and Foursquare campaign to a 29% increase in profits.