@Bass: Of course. But launching an application doesn't have to be user initiated if  it doesn't make sense to do so (receiving an IM, checking for email, getting the latest news/weather) and neither does the decision of when the OS can best reclaim resources from an application that isn't busy. There isn't an actual need to distinguish between an application that is"running" (however you define that) and something that is "not running". The end user shouldn't ever have to know.