Parks Associates (www.parksassociates.com) estimates that mobile app revenues in the U.S. and Canada will reach nearly US$22 billion in 2017, fueled mainly by in-app purchases and in-app advertising revenues.

"Tablet owners show a greater tendency than smartphone users to make in-app purchases, with more than 20% having upgraded from a free to a paid version of an app," said Harry Wang, Health & Mobile Product Research, Parks Associates. "The mobile app market has entered a new, more mature stage where companies need to employ precise segmentation and deployment strategies in order to generate consumer interest and realize successful monetization."

Apps are also increasingly becoming embedded in real world objects - with companies such as Johnson Controls wiring commercial buildings, or Samsung launching Android-controlled fridges, adds Steve Willmott, CEO of 3scale. "his shift begins to blur the distinction between online and offline, he adds.