True, but watching videos can be done entirely in passive mode. It is also very clumsy to flick forward and backward to rewatch a fact you didn't catch the firs

True, but watching videos can be done entirely in passive mode. It is also very clumsy to flick forward and backward to rewatch a fact you didn't catch the first time you watched it. Actually come to think of it, that might be really interesting data the Khan Academy is sitting on: how often people try to rewatch a part of the video. Could be an indicator if they are really learning, or pseudo learning. Or maybe it is only me who sometimes needs to rewatch parts.