The way Android handles permissions within apps has been completely revamped to give users absolute control. This is rather advanced, but it basically gives users more control, peace of mind, and privacy with their devices and what apps can do on a device.
With Android 5.1 you see what permissions the app needs when you install it, as shown in our screenshot. With Android 6.0 the apps will have to ask permissions first when you USE that specific feature. Instead of all or none like in the past. If something wants to access your camera, you have to approve that permission, same goes for location data, etc. This means rogue apps can't access the internet without your approval first. Making Android safe, more secure, and protecting us on an app-by-app basis.
Users can even head into settings > apps > open an app and revoke permissions whenever they'd like.