I closely monitor about 300 of our keywords. Sometime in the past 24 hours 210 of them dropped significantly. That's the sharpest drop I've seen since Panda 1.0 (we lost 230 keywords that day). I'm hoping it's just some bouncing around like I've noticed lately and not a sustained drop, but I don't have a good feeling about it.
Oddly, our traffic so far this morning isn't as devastatingly low as it was after the Panda 1.0 drop in kw. It's lower than I would expect, however.