Founder and executive director, Khan Academy
Age: 35
Industry: Nonprofit
Since we profiled the hedge funder turned online educator a year ago, growth has exploded: 200,000 unique users per month have turned into more than 3 million; people have viewed his virtual tutorials some 70 million times and completed 100 million exercises. His staff has grown to 17, and he's now putting his lessons in brick-and-mortar schools with a pilot program in California, where 50 classrooms are using his platform as their core math curriculum.
Stage star: Khan's 2011 talk and follow-up interview with Bill Gates was one of the most buzzed-about sessions at this year's TED conference.
NEXT: Tony Hsieh & Charles Best (tie)
