For most of the history of film, if you wanted to insert something into the picture that didn't exist, the camera had to be stationary. Motion tracking allows artificial objects to be inserted convincingly into real footage. Phil Rhodes explains
This is an astonishing technology demonstration: A camera tracking a bouncing ball in real time, keeping it in the centre of the video image
The technical challenges faced by NASA in bringing back video footage from Mars are so gigantic that most people would give up before they started. So it seems churlish to even suggest that the footage we've seen so far (especially of the landing) was a bit, you know, jerky.
This is just a bit of fun, but consider for a moment the range and depth of skills that went in to this amazing piece of work
Asus prepares to bundle Leap Motion controller in a sensational boost for motion control user interfaces. This really could be the future of video editing