Hi Sal, I have started to use Khan Academy this year and it has helped me to pass all my college math classes. I haven't seen your history videos, but it seems to me that Clemens thinks that your videos are the only resource we use to study the various topics your cover. That's like saying I only watch your math videos, but I'll never open my text book to do practice problems on differential equations.In the same respect if I were to watch your history videos I would be looking for a timeline and overview to give myself structure for what I should study and look at in more depth.

Thank you for all your hard work, we all appreciate it.

Adam