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.
Developing apps for mobile devices requires considering the constraints and features of these devices.
Today all highest paying mobile ad networks are laser focused on mobile as the fastest growing digital advertising sector.
Some companies offer apps as an alternative method to deliver content with certain advantages over an official website.
Usage of mobile apps has become increasingly prevalent across mobile phone users.
The user is often the focus of interaction with their device, and the interface entails components of both hardware and software.
User input allows for the users to manipulate a system, and device's output allows the system to indicate the effects of the users' manipulation.
Developers also have to consider a wide array of screen sizes, hardware specifications and configurations because of intense competition in mobile software and changes within each of the platforms (although these issues can be overcome with mobile device detection).