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Many of the free apps on the store use advertisements and are freemium – free apps with in-app purchases used as the sources of revenue.
Play Store is Google’s official pre-installed app on Android-trademarked devices which provides access to content on the Google Play Store. It allows users to browse and download music, books, magazines, movies, television programs, and applications. With the introduction of Google Play on March 6, 2012, the Android Market app on old devices was upgraded to the Play Store app.
Play Store filters the list of applications to those compatible with the user’s device. In addition, users may face further restrictions to choice of applications where developers have tied-in their applications to particular carriers or countries for business reasons. Carriers can also ban certain applications, for example tethering applications.
There is no requirement that Android applications be acquired using Play Store. Users may download Android applications from a developer’s website or through a third-party alternative. Play Store applications are self-contained Android Package files (APK). Play Store does not install applications; it asks the device’s PackageManagerService to install them. The package manager becomes visible if the user downloads an APK file directly into their device. Applications are installed to the phone’s internal storage, and under certain conditions may be installed to the device’s external storage card.
The Play Store application is not open source. Only Android devices that comply with Google’s compatibility requirements may install and access Google’s closed-source Play Store application, subject to entering into a free-of-charge licensing agreement with Google. In the past, these requirements had included 3G or 4G cellular data connectivity, ruling out Android-powered devices comparable to Apple’s iPod Touch, but this requirement had been loosened by the 2011 release of the Samsung Galaxy Player.
Some tablet computers such as Amazon Kindle Fire, do not provide access to Google Play, and instead use their manufacturer’s own mobile content distribution service. Some owners use Android rooting to access Google Play, or use sideloading to load applications. As of July 2013, Barnes & Noble released an update to the Nook HD adding Google Play. Some applications, upon downloading from Google Play, elicit a warning that they are about to overlay the previously loaded Nook version of the same application. BlackBerry 10 devices (OS 10.2.1 and higher) can sideload an app called SNAP which allows direct downloads of apps from Google Play