comScore has published its latest stats for smartphone market share in the US: not for new sales, but for the devices actually being used by people. As elsewhere, the market is carved up between Google’s Android and Apple’s iPhone, although the gap between them is much narrower than in recent analyst figures for new sales of handsets. comScore estimates that iPhone accounted for 40.6% of smartphones in use in the US in September, while Android’s share was 51.8%. It’s then a long drop to BlackBerry (3.8%) and Windows Phone (3.3%). Overall, comScore thinks that 147.9m Americans now own smartphones, accounting for 62% of all mobile phone owners there. The company has also published its latest numbers for the most popular mobile sites and apps across iPhone and Android, with Facebook topping the apps list with 74.3% penetration among owners of those devices. YouTube’s app is used by 49.6% of iPhone and Android owners in the US, while Pandora Radio is used by 49.3% – more popular than Gmail (44.9%), Google Maps (43%), Instagram (25.9%) and Twitter (21.1%) among others.