Richard Ludlow, 23
New York City
We first profiled Richard Ludlow last fall, when he was a finalist in our annual roundup of young entrepreneurs with big potential. At the time, Ludlow had turned down a job offer from McKinsey and deferred Harvard Business School in order to start angel investor-backed Academic Earth, a site with videos of university lectures and other educational content. Ludlow's mission hasn't changed: expand access to high quality education for free online and eventually make the for-profit operation sustainable through ad sales and affiliate marketing. The site, which is still pre-revenue, now features lectures from Berkeley, Harvard, MIT, Princeton, Stanford, and Yale. Ludlow and his two full-time employees and handful of part-timers and contractors are working on tools that will allow users to post questions and answers, browse video transcripts, and search within the videos themselves for specific clips. The Yale grad says he deferred Harvard again and is in talks with more schools about including their videos on the site, which he says had more than 200,000 unique visitors in February.