iPhone 4S helps iOS close the gap on Android

Among Americans who bought a new smartphone in the last three months, 44.5 percent of those surveyed in December purchased an iPhone, putting Apple's handset just behind Android smartphones, which were picked up by 46.9 percent of December respondents, according to Nielsen. RIM's BlackBerry came in at 4.5 percent.That finding stands in stark contrast to results from Nielsen's October survey of