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If you're a true fan, seeing what the people involved in the creation of the series thought about certain moments in an episode can be lots of fun. On the other hand, it's a lot easier to do for the cast than to record voiceover commentary on top of the DVD edition - the way it's usually done. Plus, it's interactive: cast members will also answer fan questions, and fans will be able to follow Twitter streams online, or on-air, in a scroll at the bottom of the screen.