Social networking sites such as Facebook have contributed to a staggering increase in the number of mobile app users.
According to ComScore, social networking apps grew their US user base by 240% to more than 14.5 million mobile users from April 2009-April 2010.
Other categories boasted even more users, including weather apps at more than 18 million and maps at approximately 16.8 million.
"Social networking is by far the fastest-growing mobile activity right now," said comScore senior VP Mark Donovan.
"With 20 percent of mobile users now accessing social networking sites via their phone, we expect to see both application and browser usage continuing to drive future consumption of social media."
Donovan added that the "most-used app" across nearly all smartphone operating systems also fell into the social networking category.
"The top social Website, Facebook, is entrenched as the most widely used app by owners of BlackBerrys, iPhones and other smartphones. Only users of Google's Android operating system are more likely to use Google Maps than Facebook."