For Bobby Gruenewald, using a smartphone is a religious experience. Or at least it can be, now that the Oklahoma pastor has built the YouVersion app, which reimagines the Bible for the digital age, letting users record reflections, choose reading plans, and share passages online. "The printing press was revolutionary to the Bible," says Gruenewald. "Today, everyone has a printing press." You Version has amassed some 16 million downloads; its users have spent more than 83 million hours browsing pages.