This looked interesting:

Need help with class? YouTube videos await
http://r.smartbrief.com/resp/nTbgszvsnxvyrhCibSoajfTz?format=standard

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Math videos won't rival the millions of hits garnered by laughing babies, but a YouTube tutorial on calculus integrals has been watched almost 50,000 times in the past year. Others on angular velocity and harmonic motion have gotten more than 10,000 views each.
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Educated at Harvard and the Massachusetts Institute of Technology, Khan developed his tutoring hobby when a younger cousin was having trouble with sixth-grade math. As word of his knack for teaching spread among relatives and family friends, Khan got tired of explaining the same things over and over, so he created videos and posted them on YouTube. He formed the Khan Academy, currently a one-man show, with the long-term goal of starting a school that uses technology to customize learning for students.

Khan's video clips have developed a following far beyond that immediate circle of relatives and friends, and now he gets dozens of e-mails a week from around the world � including requests for videos on specific topics and help solving particular problems. He now claims about 600 videos on subjects spanning math, physics and even the tanking economy.