Recently Windows Blue Build 9374 got leaked over the web. One of the new features it revealed was the new Kiosk mode in Windows 8. Under Users Settings menu, you will have option to lock down your device to a single immersive app experience. This will allow anyone to set a limited functionality for an user account or select an app to automatically launch an app on login.
Pretty neat feature for users who often use their device to demo or for public use.