CEO, NingAfter News Corp.paid $580 million for MySpace in 2005, every Tom, Dick, and Terry (Semel) wanted a social network of his own. Ning's neat trick: Letting anyone build social-network applications for free on its Web-based software platform. In just a few years, Ning's already gathered more than 60,000 such social applications. In Bianchini's network: Her cofounder, Netscape wunderkind Marc Andreessen.
View all candidates
Tell us who you think matters now -- and why