With more consumers using smartphones and connected devices like the iPad, there is no avoiding the importance of mobile apps. Apps are responsible for 56 percent of all smartphone activity according to data shared by Jonathan Carson, CEO of Telecom at Nielsen, during Nielsen’s Consumer 360 conference.

According to Nielsen’s latest survey of mobile app downloaders, that is, consumers who have downloaded an app in the past 30 days, if you want to understand the consumer landscape for mobile apps, you have to understand the Apple iOS and Google Android ecosystems.

Even though mobile phones tend to be thought of as personal, it is not unheard of to have other people download apps onto one’s phone.

According to The Nielsen Company’s latest research on mobile applications, most mobile app downloaders are concerned about privacy when it comes to sharing their location via mobile phone.

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.

Smartphone adoption and use of mobile applications is rapidly increasing… what are the most popular apps and who is driving the growth?

According to The Nielsen Company, mobile Internet traffic in December 2009 was similar to total Internet use, with the largest audiences being seen for search, e-mail and social networking.