New Olympics Cam Also Coaches. NBC is using fancy technology in its Olympic coverage to infuse drab races against the clock with the thrill of a real race. It's also caught the eye of coaches. By Jeffrey Benner. [Wired News]
The software tracks the focus and angle of the camera, allowing the coach and athelete to view the differences in their performance on multiple runs. This in turn helps them evaluate the best line for a particular race.
This tech could also be used to make an army appear using a limited number of actors and overlaying/compositing their various positions for new lower cost crowd scenes.
I also seem to recall a similar technology being used to remove people from the picture entirely, so that you can see what an area looks like without anyone in it, but with the same camera tracking as before.