Google still rules in search, with two-thirds of the market, and its influence keeps expanding as adoption of its Android mobile phone operating system soars. (It gives Android away for free to phone makers.) The stock is up 18% over the past year. A new era begins in April when co-founder Page, 38, takes over as the search giant’s chief executive officer, replacing Eric Schmidt, who will become chairman. His personal passions include buying up chunks of residential Palo Alto for a network of houses that use new types of fuel cells, geothermal energy, and rainwater capture. He also rides a Zero X electric dirt bike and an electric sports car from Tesla Motors, in which he and Google co-founder Sergey Brin are investors.
Net Worth: $20.6 billion