This month American Express started promoting mobile payments to consumer, small business, and corporate cardholders in Canada and the U.K. who use Android devices (KitKat 4.4 or higher). Amex calls its payment application, which is available in the American Express Mobile App, Amex Pay. The Android operating system uses host card emulation software to support NFC contactless payments at the point of sale. Cardholders can enroll in Amex Pay with a few taps. When they do, the American Express Token Service delivers a token to their phone. When purchases are made at merchants using contactles...