FTA: "Exercises will be coming in the next release."

Looks like this first release is a viewer+, but impressive iterations will not be far behind.

The breadth of Khan Academy's granularity for interpreting a student's understanding is staggering. The second half of Salman's Ted Talk shows how granular it gets: http://www.ted.com/talks/salman_khan_let_s_use_video_to_rein...

In my opinion, the most impressive part of the Khan Academy approach is the emphasis they have put on demonstrating a student's understanding of the concepts - as demonstrated in that Ted Talk. The fact that the entry-point is "videos on the web" is a simplification of their overall mission.