The videos were uploaded to YouTube 10 months ago by someone called d3vienno. I tried to track him down. I sent him an e-mail and did a Google search that returned several results, none of them very helpful. This is someone who says about himself: "Just a random Swedish guy obsessed with D3.js, trying to share his (limited) knowledge." Well, thanks for that, sir. So far, I've gone through the first 7 videos and they are good.
(UPDATE: d3vienno has answered. His name is Robin Lindeborg. He's a Swedish data journalist. Follow him on Twitter and say thanks!)
*Scott and I are thinking about teaching a MOOC (Massive Open Online Course) together at the end of 2014 or beginning of 2015. We'll keep you posted on this. It should be fun.