comScore has published its latest research into the US smartphone market, tracking the devices that are actually in use (versus sales or shipments for the last quarter). In August 2013, the company says that Apple had the biggest share of individual manufacturers with 40.7% of in-use smartphones, ahead of Samsung (24.3%), HTC (7.4%), Motorola (6.9%) and LG (6.7%). However, Android is still the most popular software, with a 51.6% market share compared to iPhone’s 40.7%. Interestingly, Android slipped a bit since May 2013, while iPhone grew slightly. BlackBerry (4%) and Windows Phone (3.2%) remain niche players. comScore has also broken down the 15 most popular smartphone apps in the US, noting that Facebook is being used by 75.7% of smartphone owners. YouTube has a 52.8% share, and Pandora Radio 43.3%, with other notable inclusions in the chart being Instagram (27.4%) and Twitter (21.7%). Instagram more popular than Twitter? That’s a new thought.