The combined value of paid apps, app-enabled purchases of goods and services and in-app advertising is expected to double to $151 billion in the U.S. by 2017, AppNation said.Related StoriesiPad rumour rollup: iPad 5 coming September, iPad mini 2 delayedApple to investigate death of woman who was electrocuted by charging iPhone 5Toddler plays with dad's iPhone, accidentally buys car
