• by Mark Walsh  @markfwal, June 1, 2012

Half the smartphones in the U.S. ran on Google’s Android platform through April, according to the latest mobile market data from comScore. Android’s 50.8% market is essentially unchanged from March, but up slightly from 48.6% at the start of the year.

About half of users are both downloading apps and using mobile browsers, up from less than 40% in the year-earlier period. More than a third (36%) are going to social networking sites or blogs, a third play games, and almost 26% listen to music on their devices.

Apple’s iOS claimed almost a third (31.4%) of the market as of April, trailed by Research in Motion’s BlackBerry (11.6%), Microsoft’s Windows Mobile/Windows Phone (4%) and Symbian (1.3%). RIM’s share is down from 12.3% in March and 15.2% in January, underscoring its losing battle to maintain its customer base against Google and Apple.

Microsoft and Symbian also continue to see shrinking smartphone market share. More than 107 million Americans overall owned smartphones in the three months ending April, up 6% from January. That translates into smartphone penetration of about 46%.

Among mobile phone manufacturers, Samsung remained comfortably at No. 1, with 25.9% share, followed by LG (19.2%), Apple (14.4%), Motorola (12.5%), and HTC (6%). Samsung overtook Nokia to become the world’s largest phone maker in the first quarter, with global market share of 20.7%, according to Gartner.

Text messaging remains the most popular non-voice mobile activity, with some 74% of mobile users texting -- about the same as in January, and up from about 70% a year ago. In the U.S., carriers’ flat-fee SMS packages appear to be keeping alternative messaging services, like Facebook and Apple, from wiping out their cash cow.