Free Knowledge Culture Calendar/September 23

 Today in 2008 the first Android-based mobile phone was launched. Advances in energy efficiency and battery technology led to a decline in PC sales in favor of mobile devices towards 2010 (post-PC era). Following the introduction of the iPhone and 3G mobile networks, Android accompanied the mobile web to a wider audience. Building on the success of iTunes, the reinvention of the online software repositories of Linux as the "App Store" concept contributed to the popularity of the platform. The Linux-based Android system became the most popular operating system of all time. Although it has a core of Free Software and the introduction of Linux operating systems achieved a major breakthrough with Android, parts of mainstream Android distributions are proprietary – including a backdoor.