In the five years since the iPhone hit the market, Apple and Google have delivered more than 40 billion cumulative downloads of apps. Other sources predict the growth has only just begun and that the app marketplace will swell from 31 billion downloads worldwide in 2011 to over 66 billion downloads in 2016.

This report examines the app genres primed for growth, the trends that will shape the mobile app market over the next few years, and some of the challenges the industry will face, as well as companies to watch.

Thumbnail image courtesy of flickr user blakespot