Android’s U.S. market share hits 53% by Seth Weintraub @FortuneMagazine January 31, 2011, 6:12 PM EDT E-mail Tweet Facebook Google Plus Linkedin Share icons Is there an ARMDroid Dualopoly on the horizon? In the biggest news item about Android market share since this morning, NPD group announced that in the US, Google’s GOOG Android now outsells all of its competitors, combined. It is important to note that NPD’s data doesn’t track corporate/enterprise mobile phone purchases, so RIM’s RIMM Blackberry and to a lesser extent Apple’s AAPL iPhone may be under-represented. But for people who have a choice (and don’t let their IT department choose for them), Android has become a compelling choice. Android’s smartphone operating system (OS) significantly increased its market-share lead by 9%, since the prior quarter, to reach 53% of the U.S. consumer smartphone market. According to The NPD Group, a leading market research company, Apple iOS share declined 4% to comprise 19% of unit sales in Q4; RIM OS fell 2 points to tie Apple’s 19%; Windows Mobile, Microsoft’s legacy OS, fell 3 points to 4%, as the new Windows Phone 7 OS debuted at 2%; and Palm’s WebOS held at 2%. Android use is…shall we say…exploding.