30. Salman Khan
Salman Khan
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.


Last updated October 25 2011: 5:11 PM ET
Join the Conversation
Ones to watch

In addition to Fortune's 40 Under 40 list, we're also keeping our eye on these 20 innovators, young guns from a wide range of industries and backgrounds.

Search for Jobs

Video