As of March 2017, there were some 2.8 million apps available in Google Play, the world’s largest app store, while the Apple Store, the second ranked, boasted some 2.2 million available apps in January 2017. As mobile apps become more popular and mobile internet more widely available, revenues generated from applications are reaching unprecedented records. In 2016, it is estimated that worldwide app revenues including in-app ads and app store sales will amount to 88 billion U.S. dollars, but this figure is expected to more than double by 2020.
There are a number of different ways in which to generate revenues from apps, including simply charging users a small amount of money per download, but this is not the most popular monetization models among worldwide mobile developers, which claim to use it in some 20 percent of the cases. In fact, statistics show that the number of apps in Google’s Play Store that charge for download has decreased 2015 compared to previous years. A variant of this model is the upgrade, where a free application will offer users the possibility to upgrade to a more enhanced or ad-free version of their product in exchange of a fee. The most widely used revenue stream is advertising, but, according to developers, also the most hated . In-app advertising revenues are set to reach 117.2 million U.S. dollars in 2020, up from 40.5 billion U.S. dollars in 2015.