Windows 8 has a really useful feature that lets two apps run side-by-side, and they automatically share just the right amount of screen space.
While running one app, two-finger swipe from the left to show the Recent Apps bar. Drag one to the right or left side of the display, and the main app will make some room for your second app. This is a great way to, say, chat while you’re watching a video, or take notes in a text app while you’re doing research in a browser, but not have to mess with rearranging your windows. Windows 8 handles it automatically.