Personally I think it's a great way to master your skills. But what happened for me was, it pointed out my weak areas which even I didn't know like for example:Significant figures. Maybe I missed it or I was asleep while this topic was going on in school. But on the way going through mastery skills I got that covered. So wow thanks so much. Maybe it will help me clear my computer programs of some errors or maybe so much more. So I would advice every one to go through those buzzer questions.

When I heard of Khan academy I had a biased opinion because of it's Indian name mostly because the education system in India. But when I literally went through the website I was very much convinced that this is my personal teacher from which I can benefit so much in life. And when I saw the videos about how Mr. Khan has his opinion about learning, his opinion had a great influence!