Most adults in the U.S. now have cellphones and one in four are using smartphones. With their rich features and capabilities, these devices are driving the mobile app economy. As of June 2010, 59% of smartphone owners and nearly 9% of feature phone owners report having downloaded a mobile app in the last 30 days.

To better understand the growing popularity of mobile apps, The Nielsen Company launched the Mobile Apps Playbook in December 2009. The most recent version is now available. "The State of Mobile Apps," features select highlights from the report and is based on an August 2010 survey of more than 4,000 mobile subscribers who had reported downloading a mobile app in the previous 30 days.

One of the main challenges facing apps publishers is making sure consumers “discover” their apps. According to Nielsen’s survey, searching application stores on their phones is the preferred way for discovering new apps for users of feature phones and smartphones alike (57% and 40%, respectively). The next most popular “preferred” form of app discovery is through the recommendation of a family member or friend. However, smartphone apps users are more likely than feature phone users to seek out other ways of discovering new mobile apps.

For more facts and insights on mobile app usage, mobile advertising and who's paying for apps, download Nielsen's "The State of Mobile Apps."