How I Use It
I've used to teach about the French Revolution. It's a great resource to expose students to a condensed and thorough summary of the events and people that affected this event in History. References to other websites or sources or even primary sources aren't always there, which is something that would be appreciated.
Khan Academy's videos cover not only Mathematics topics but also a wide variety of other subjects. The explanations provided for History or Science are great to engage students and help them corroborate/complement what they have learned.