Windows 8's new Start screen has tiles to allow you to use apps more easily and check updates, alarms, and information at a glance.
Windows Store Apps: An app installed on the Start screen is arranged and displayed in tile format.
Desktop Tile: Switch to Desktop.
Screen Scroll: Scroll the Start screen horizontally.
Zoom Out: You can quickly move to an app you want to use by zooming out from the Start screen to see the entire screen at a glance.