Yup, brian had to step in and win.
Since Tiger believes in the parallel angles theory you HAVE TO OVER-ROTATE YOUR LEFT ARM past the "1/4 turn" to the plane almost every swinger uses.
Try it out: Get to the "end" of a very normal swinger's backswing. "Do it right" and you'll end up with a nice flat left wrist and a clubshaft pointing "down the target line." Now, keep in mind if you can't get the club to parallel it will LOOK "laid off" but it isn't. Why? Because you are still pointing to an extension of a plane line. Now rotate your left arm MORE while keeping a flat left wrist, what happens? I'll tell you: You'll end up with a club that is "laid off" and that points OUTSIDE the plane line.
So, how does this factor in to him hitting it right?
If he doesn't rotate that forearm back to the "1/4 turn" position he will way out to the right and leave right if he holds it off or if he flips it he'll hook it. Next time you are watching tiger play i want you to either use your DVR or Tivo to watch his swing frame by frame.
If you find a swing of his that gets to parallel stop the DVR/Tivo and hold up your remote control to be inline with the clubshaft and watch how far outside the ball it points. Now i want you to go frame by frame in his downswing, if he gets that left forearm rotated BACK the butt end of the club will point at the ball again and he'll hit a great shot 99% of the time. If he doesn't get that left arm rotated back to where it should be, FOOOOOORE RIGHT!
Now some of you may not agree with me but Brian and Non-Authorized does so I think i'm coverd