Had never heard of this video and am guffawing as I watch. I LOLLed, literally, when I reached the part where one of the math guys says Salman Khan "really ought to do a handwriting video, too."
Karim Kai Ani (Khan Academy: The Hype and the Reality) says Khan replaced the video, but quotes Khan's reaction as: “It’s kind of weird...when people are nitpicking about multiplying negative numbers.”
Question: Why is Salman Khan a rock star?
Because that's what he is. He was the keynote at this year's so-called Celebration of Teaching and Learning, and he was a rock star. They had to post guards outside the room where he gave his workshop to keep the crowds out.
I blame the multi-verse.