Google's Android operating system powered 50.8 percent of U.S. smartphones in April 2012, down from 51 percent the previous month but up from 48.6 percent in January, according to digital research firm comScore. Apple's iOS follows Android at 31.4 percent, increasing from 29.5 percent in January.

More than 107 million U.S. subscribers owned smartphones during the three-month period ending in April, up 6 percent versus January, comScore reports. Research In Motion's BlackBerry continues to fade, slipping another 3.6 percentage points between January and April to make up 11.6 percent of the U.S. smartphone market. Microsoft's Windows platform slipped from 4.4 percent in January to 4 percent in March, and Symbian fell from 1.5 percent to1.3 percent.

Text messaging dipped slightly in April: 74.1 percent of U.S. subscribers sent a text to another mobile device, down from 74.6 percent in January. At the same time, 50.2 percent of subscribers used a downloaded app, up from 48.6 percent in January, and 49 percent accessed the mobile browser, up from 48.5 percent three months earlier. In addition, 36 percent accessed a social networking site or blog in April (up from 35.7 percent in January), 33.1 percent played games (up from 31.8 percent) and 25.8 percent listened to music on their phone (up from 24.5 percent).