Digital Trends - Market research firm Nielsen has released new figures on smartphone ownership and U.S. marketshare during the third quarter of 2011. The leading numbers aren’t too surprising, with Android accounting for 42.8 percent of the market, Apple’s iOS coming in second with a 28.3 percent share, and RIM’s BlackBerry platform managing a 17.8 percent share. However, in what might be a challenge for Microsoft, the Redmond software giant saw its combined share for Windows Mobile and Windows Phone slide from 9 percent in the first quarter to just 6.1 percent in the third quarter.