Hi! The Net Is Calling.

Like the technology he's pushing, Jeffrey Citron, the 34-year-old CEO of Internet phone company Vonage, has a tendency to shake things up. In the 1990s, armed with little more than a high-school diploma, he founded two businesses, including Datek Online Holdings, and helped pioneer the tools for computerized daytrading on Wall Street (and attracted the ire of the Securities and Exchange Commission, which fined him $22.5 million for allegedly misusing the new system). In 2000, he began pouring his own money—$70 million and counting—into Vonage, an upstart telephone company that is now revolutionizing this $1 trillion industry.