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They weren't "pulled."

They were put into the beta as a special feature that you had to be a registered developer to even unlock (unlike the mute/lock switch feature that didn't have this requirement).

They want App developers to have plenty of time to design around these gestures and make sure that their own gestures don't conflict. Expect them to debut for consumers in iOS 5, which will probably be announced by the end of March.
 
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