Just like common people know that android has two displays mode, portrait (vertical) and landscape (horizontal). Have you ever experienced such a thing: you have set the portrait mode but it turns out that there are a number of applications staying on the Landscape mode when you open the applications?
Usually, this happens when you open the android applications while lying down in the bed. It should be so annoying moreover you have set the mode to be portrait. Indeed, there are a number of applications that are automatically to be landscape, for example Path, Resize MyPix and some other applications.