By Q2 2015, the Google Play and Apple stores alone generated billion.
An analyst report estimates that the app economy creates revenues of more than €10 billion per year within the European Union, while over 529,000 jobs have been created in 28 EU states due to the growth of the app market.
Mobile user interface (UI) Design is also essential.
For apps with a price, generally a percentage, 20-30%, goes to the distribution provider (such as i Tunes), and the rest goes to the producer of the app.
In 2009, technology columnist David Pogue said that newer smartphones could be nicknamed "app phones" to distinguish them from earlier less-sophisticated smartphones.
Most mobile devices are sold with several apps bundled as pre-installed software, such as a web browser, email client, calendar, mapping program, and an app for buying music, other media, or more apps.
Apps that are not preinstalled are usually available through distribution platforms called app stores.
They began appearing in 2008 and are typically operated by the owner of the mobile operating system, such as the Apple App Store, Google Play, Windows Phone Store, and Black Berry App World.