Most internet start-ups died long before they got old enough to earn a living. But eBay skipped adolescence entirely--heading straight to profitability--thanks largely to Meg Whitman, 46, a seasoned marketing executive who in 1998 began overseeing the online curiosity that rapidly morphed into the world's most successful e-commerce company. Valued at $32 billion, eBay handles transactions worth $59 million a day, or $684 a second. Mom-and-pop shops peddle their wares alongside IBM, Kodak and Sears--and many stake their livelihood on the digital marketplace. "I think there's a minimum of 150,000 businesses that might not exist without eBay," says Whitman.
Given eBay's...