You’ve read all of your free items this month. To register, get added benefits and unlimited access to articles, Become a Member. Already a Member? Sign in. Advertising Age Article Abstract MasterCard Plunges Into Mobile With Apps and Payments Testing U.S. Marketing Chief Guerin Says Couponing Will Drive Mobile-Payments Growth By Cotton Delo, Published on April 17, 2012 2 Want more Access, Content & Connections? Upgrade to Membership. We are glad you are enjoying Advertising Age. To get uninterrupted access and additional benefits, become a member today. Register Now Already a member? Log in.