I've seen a lot of confusion and concerns about multitasking in iOS 4. I will attempt to clarify things. It's not really "multitasking". Applications do not continue to run at "full steam" when they are sent to the background. Not all apps will need to or be able to execute code in the background. Apple allows developers to declare the following "reasons" for background execution: If an app doesn't do any of those things, then it's not actually running in the background. If it's not "running", then why is it in the multitasking bar in the dock? Background applications remain in memory, even if they are not executing code. This allows for a fast switch back to the foreground. If you are concerned about memory use, don't worry. Developers are strongly encouraged to free memory-hungry objects like images before entering the background state. Also, if system memory gets low, background applications will automatically be purged from memory to prevent problems. What about apps that don't support multitasking? If an application has not been updated for iOS 4, it will not remain in the background; it will close and open like a normal 3.x application. Even though the icon shows up in the multitasking bar, it's not being treated like a real background app. ... Source(s): Apple Developer Documentation Please post other questions/concerns (and answers if you want Please Register or Log in to view images), and I will add them to this post. Also, if I made a mistake, correct me.