Deconstructing the New Mission Control Feature
Mission control is a major new feature in Lion. If you could take Mission Control apart, you would find that it is built on the foundation of Exposé, Spaces, and the Dashboard. I'm guessing that unless you are a power Mac user extraordinaire, you have never used Exposé or Spaces, even though they are both great features. Apple recognized that these two features were underutilized, and it combined them with Dashboard and the new Full Screen windows feature to create Mission Control.
Mission Control is not only easier to use but also much more tempting to use because it has moved front and center. The Mission Control feature is accessible from the Dock, keyboard, or with multi-touch gestures, and it shows everything that is open on your system, giving you quick access to any application that is running.
One of the purposes of Mission Control is to create separate working spaces, also called desktops. This allows you to segregate your work but enables you to jump back and forth between your work areas easily.