No, the ghost of Timothy Leary hasn't been messing with your water supply. The trails you are occasionally seeing on your television screen during the U.S. Open are supposed to be there, courtesy Flow Motion technology. And just like last year, the camera trick manages to be totally cool and completely useless at the same time.
ESPN and CBS will use Orad's Flow Motion to track the movement of players and freeze their position at the point of impact for each stroke. These graphics are then overlayed on the screen to give viewers a sense of how each player is moving around the court.
Here's an example from Wednesday's Venus Williams match:
It's a neat trick, but does it aid in the viewing experience? Super slo-mo cameras allow you to see subtle differences that you might not be evident at regular or normal slo-mo speeds. The superimposed first down line in football provides an easy reference for fans to keep track of the distance remaining toward extending the drive. What does the tennis tracker accomplish?
You can see that Venus stayed near the baseline on this point and hit more backhands than forehands, but that's not information that enhances a viewing experience. You don't need fancy camera tricks to tell you that a player came to the net.
Sometimes television networks use technology just for the sake of using technology. This is one of those times. There's no problem with the Flow Motion, there's just no benefit from it either.