Twitterrific and iOS 4's Backgrounding (iOS)
Can Twitterrific check tweets in the background running on iOS 4?
No, Apple limits the types of applications that can run in the background to those that play audio, make Internet phone calls and track GPS locations. Twitterrific doesn't fall into these categories, so it does "fast app switching" instead. This allows you to quickly switch between your Twitter timeline and other apps.