• by Mark Walsh  @markfwal, March 7, 2011

Android leapfrogged BlackBerry in January to become the largest smartphone platform in the U.S., with 31.2% market share, according to the latest comScore data. Android's three-percentage-point gain from December was combined with a one-percentage-point drop by Research in Motion's BlackBerry OS to 30.4% to push the Google mobile operating system to the No. 1 spot at the start of 2011.

Apple's iOS remained the third-most-popular smartphone system, with 24.7% share in January, while Microsoft's Windows Phone platform trailed further back at 8%, and Palm at 3.2%. Separate figures released by Nielsen last week also showed Android pulling into the lead for the first time, but in a tighter race in which the Google OS had 29% market share compared to 27% apiece for iOS and BlackBerry.

In either case, it's clear that Android is eating into BlackBerry's share in a big way. In the three months ending in January, Android picked up 7.7 percentage points, while BlackBerry's portion of the market slipped 5.4 percentage points.

Among handset makers, Samsung remained the top company, with almost 25% market share compared to 20.8% share for LG and 16.5% for Motorola. Rounding out the top were RIM (8.6%) and Apple (7%). Overall, 234 million Americans 13 and older used mobile devices in January, according to comScore.

When it comes to usage, text messaging was by far the most common type of non-voice activity, with 68.1% of mobile subscribers texting -- the same proportion as at the end of October. Among other kinds of mobile data usage, downloading apps has seen the biggest gain over the three months ending in January, with a 1.6 percentage-point gain to 35.3%.

That still left downloads third, behind texting and Web browsing (37%), but ahead of social networking (25.3%), playing video games (23.7%) and listening to music (16.5%).