With the release of iTunes 11, Apple introduced much tighter integration between the content in your local iTunes library and your purchases available from iTunes in the Cloud.
The new feature displays all of your purchases in a single, unified library view and allows you to stream any movie, TV show or music track directly from your purchase history instead of having to download it to your computer.
This can be a great feature when working with limited disk space, but if you prefer to only see content that is actually stored on your computer, you can easily hide all of your iTunes in the Cloud content by going into your iTunes Preferences, and unchecking the “Show iTunes in the Cloud purchases” option found on the Store page.