Multitasking or Tombstoning and Isolated Storage in Windows Phone 7
Windows Phone 7 manages multiple active applications by implementing a stack. In a sense, this application stack extends the page stack within a single Silverlight program. You can think of the phone as an old-fashioned web browser with no tab feature and no Forward button. But it does have a Back button and it also has a Start button, which brings you to the Start screen and allows you to launch a new program.
