More than half of US consumers who've made purchases on their smartphones have done so in response to a mobile marketing message. Smartphone sales will exceed 420 million in 2011. Analysts forecast these sales will surpass one billion by the end of 2016. The way consumers are interacting with brands and connecting to the world is changing because of mobiles. Find out about location-based marketing, mobile payments, QR codes, applications, and mobile coupons. Learn how mobile marketing can increase your capabilities to retain current customers and gain new ones.