The App Effect is the name of a video clip presented by the Apple company for all the people participating in WWDC 2015 last evening, the American company demonstrating the importance of applications. In 8 years, the App Store grew to 1.5 million applications with 100 billion downloads recorded, and the applications made it possible to create an ecosystem of almost 1 billion iDevice owners around the world.
Because applications are so important for mobile terminals, the Apple company has dedicated a special video clip to them, which you can see below.
https://www.youtube.com/watch?v=fSiDIaab2nY
