Contactless cards work when you hold them 1 or 2 inches from a special radio-frequency reader. Because you don't need to show them to a cashier, swipe them, sign a receipt or enter a PIN, they speed checkout.
Visa, MasterCard, American Express and Discover are promoting the tap-and-go cards for use when buying something quick and cheap -- garlic fries at AT&T Park, a Slurpee at 7-Eleven, a prescription at Walgreens, a Happy Meal at McDonald's, or movie tickets at AMC, Loews, Regal and Cinemark theaters."
Discover is testing cell phones with contactless chips.
American Express offers the cards, which it calls ExpressPay, under its Blue line of credit cards"
It used to be that when you lost your phone, you lost all your friends. Now you can loose a credit line along with them!