According to a survey taken by comScore, as of the end of the 2009 fourth quarter, RIM had the largest market share of the mobile smartphone OS sold in the U.S. with a 41.6% piece of the pie. That is down a full percentage point from the beginning of the 3 month period. Gaining some strength is the Apple iPhone OS. The touchscreen device had 24.1% of the market last September, rising to 25.3% as the year ended. Windows Mobile finished the year third, with 18% of the U.S. smartphone OS market, down 1% from the end of Q3. In fourth place, webOS garnered a 6.1% slice which was a fairly large decline from the 8.3% share it held in September. And while Google's open source Android OS finished in last among the top 5, its 5.2% market share at year's end was more than double the 2.5% reading from the end of the 3rd quarter. While Android ended the year with great momentum thanks to the great reception given to the Motorola DROID, the momentum should continue in the current quarter with the release of the Nexus One. While the N-One itself has seemingly not performed to sales expectations, it has brought plenty of attention to the OS which could have helped the entire Android market continue to pick up marketshare at the expense of other platforms like Windows Mobile and webOS.