Occupation: CEO of Twitter
Previous TIME 100 appearances: 0
In just five years, Twitter has won the hearts of microblog skeptics, 140 characters at a time. Helmed by CEO Dick Costolo, formerly of Google, the site boasts more than 200 million users spitting narcissism without limit, with just enough brilliant morsels sprinkled throughout to make each real-time breakfast update worth wading through. Under Costolo's guidance, the elasticity of Twitter has produced celebrities, fueled revolutions and, yes, even given us the ability to know who shares our love of Pop-Tarts.
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