For App Makers, China Is Untapped and Untamed

China is emerging as the next battleground for global app makers—but cracking the world's largest smartphone market is proving to be vexing. App makers must navigate dozens of app stores with looser rules than in the U.S., fend off a proliferation of cloned apps, and steer around a thicket of regulations and intense competition from local developers. What's more, companies that charge for their apps are finding they need to get more creative about business models in China since users there are accustomed to getting most digital content free.