A comprehensive survey of mobile health apps by IMS Health found that there are now more than 165,000 of them on the market. But just 12% of the apps account for 90% of all downloads. Most health apps are sparsely used, and consumers (not to mention doctors and regulators) are overwhelmed by their sudden proliferation. Almost a quarter of the apps are aimed at disease treatment or management, while two-thirds are aimed at the less ambitious goal of improving health and wellness. And 10% of apps connect to another device or sensor. The proportion of apps that connect to social networks has increased from a quarter two years ago to one-third of them today. Finally, there are 300 clinical trials that deploy mobile health apps, up from 135 two years go. More