The Richest Gaming Start-Ups You've Never Heard
With over 10 million users, Modern War's fans could make up a small country. Of course, that's part of the game's appeal: players team up for missions in which they compete to take over the world.
Japanese developer GREE has produced other combat games such as Knights & Dragons and Crime City and it's one of Japan's largest social networking services.
Analysts attribute the company's success to its track record of investing in developers.