• by Mark Walsh  @markfwal, September 15, 2010

This must be unofficial Appalooza week. With new reports from Nielsen and the Pew Research Center on mobile apps already this week, comScore weighed in Wednesday with its own quarterly findings on mobile use, including apps.

The Web measurement firm found 31.4% of U.S. mobile users had downloaded an app for the three-month period ending July, up from 29.8% the prior quarter. Those figures correspond closely with the data Pew released yesterday, showing 29% of mobile users had downloaded an app in the last month. The comScore sample is a bit broader, including cell users 13 and older as opposed to only adults.

But the small uptick in app use tracked by comScore didn't come at the expense of Web browsing. One third (33%) of mobile subscribers went on the mobile Web, up from 31.1%, as of April. Other mobile content categories saw slight gains as well. People accessing social networking sites or blogs via handsets increased from about 20% to nearly 22%, while the proportion of mobile music listeners went from 13.8% to 14.5%. The mobile gaming population remained flat at just over 22%.

Texting remained by far the most pervasive non-voice mobile activity, with two thirds (66%) of mobile users exchanging messages.

Looking at U.S. market share among smartphone platforms, comScore provided further evidence of Android's rapid ascent, with 17% share, up from 12% in the previous quarter. The increase cut into the share of Apple's iOS, which slipped to 25.1% from 23.8%. Microsoft's Windows Mobile also lost ground, dropping to 11.8% from 14%. Palm remained the same with a 4.9% share and Research in Motion's BlackBerry OS remained the top platform, with 39.3% share, down from 41.1%.

Gartner last week predicted Android will overtake BlackBerry as the world's second largest smartphone operating system by year's end and by 2014 will have a nearly 30% market share, rivaling that of Symbian. For now, rising smartphone sales continue to benefit all players.

In the U.S. 53.4 million people own smartphones, up 11% from April, according to comScore. That amounts to 22.8% of mobile users with high-end phones. Nielsen has projected smartphone penetration will surpass that of regular phones by the end of 2011.

When it comes to phone manufacturers, Samsung remained at the top, with a 23.1% market share, up a percentage point from April. Second-place LG was roughly flat at 21.2%, followed by Motorola, which fell to 19.8% from 21.6%, RIM,  at 9%, and Nokia at 7.8%. The Finnish phone giant took a big step toward turning around its sagging fortunes in the U.S. with the hiring of former Microsoft executive Stephen Elop as CEO. Nokia Chairman Jorma Ollila said Tuesday he'll step down in 2012.