Hi zhemao, thanks for the comment! I'm a Khan Academy developer. I just wanted to add that we do hire educators. Among them are Beth and Steven who are our in-resident art history faculty (http://www.khanacademy.org/about/the-team). We also have a dedicated School Implementations team (http://ka-implementations.tumblr.com/) working directly with schools to understand how Khan Academy can be integrated in classrooms and to evaluate our performance against independent test results.

Thanks stchangg! I'm on Khan Academy's school implementations team and just wanted to add that Maureen, who is also on the school implementations team, is a former 6th grade teacher. This summer, we also have 2 experienced math teachers working with us to flesh out a significant amount of our math content: Chris Talone (teacher at Marlborough, a girls' school in LA, who taught 7 levels of math simultaneously with Khan Academy this past year) and Jesse Roe (teacher at Summit, a charter school in San Jose, who taught Algebra and Geometry to 9th graders with Khan Academy this past year). We're really grateful for their thoughtful contributions which are grounded in years of experience teaching math to lots of different types of students.

Thank you for the great work you're all doing at Khan Academy. Also, I'll take this opportunity to give a small suggestion :-)

I was wondering if you guys could make Mathematics more problem solving centric (see www.artofproblemsolving.com for an example approach. Also "The Art and Craft of Problem Solving" by Paul Zeitz and George Polya's "How to solve it")

Most of the Mathematics in school curriculum is just plug n' chug work at a slightly higher level. Students do not get any insights into how really good problem solvers solve tough problems. Mathematics competitions such as the regional and international olympiads give students an exposure to such type of problem solving, but this experience is limited to a narrow pool of students who through pure serendipity discovered how intellectually rewarding problem solving can be. Perhaps if training materials were more widely available, more students would be able to get a glimpse of Mathematical problem solving at a totally different level.

In a previous life, I used to tutor O-level and A-level students in Mathematics in Singapore. The transformation some of them had when exposed to say principles in Polya's "How to solve it" was phenomenal. All too often I wished I had access to more easily accessible training materials that I could give them (and that I myself could learn from!). I'm sure there are plenty of teachers in my position all over the world.

I'd really like to see you guys team up with someone like Dan Carlin (Hardcore History) or the guys at Crash Course World History to get more history material out there.

They seem to have the right levels of exceedingly INTERESTING history along with getting narrative out about why X is important or Y is to us today, etc

Why would you want that? Khan academy has tons and tons of data on what is effective. They can (and I hope they do) run statistical test to figure out what the best method of teaching is, what works and what doesn't.

Involving humans, even experienced once, just bring in all kinds of crazy, irrational, beliefs about what works and what doesn't.

It sounds mean and dismissive, but it's a point that's been proven over and over again. Thanks for saying it.

I think that Khan Academy is providing small nuggets (videos, quizzes) of content.

As a teacher, I can take Mr Khan's currants and bake my own cake with them (i.e. use their stuff to support part or all of a course). I pick and choose, but of course my students know the site and they can pick and choose as well.