20. Daniel Ek & Yoshikazu Tanaka (Tie)
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Ek (left) and Tanaka (right)

Daniel Ek
Age: 29
Co-founder and CEO, Spotify

Ek brought his much-buzzed-about Swedish music streaming service to the U.S. last year amid hopes he'd swoop in and save the music biz. His ballyhooed hookup with Facebook offered plenty of extra juice. So is it a hit? Spotify operates in 15 countries and claims 15 million active users, 4 million of whom pay for ad-free listening. Those numbers are dwarfed by Pandora's 54.9 million users, but they are growing fast and revenue is way up (150% in 2011, by some estimates). So, it must be said, are its losses thanks to mounting licensing fees (it isn't yet profitable). Still, Ek's tech savvy and vision have earned him the ear of the industry.

Top travel tip: Dig that neck pillow.


Yoshikazu Tanaka
Age: 35
Founder and CEO, GREE

Tanaka presides over a world of opal-eyed digital zombies and pirates. GREE, the mobile social-gaming company he founded in his apartment in 2004, has become Japan's biggest social network -- of any kind. Globally it reportedly has 190 million users and expects to generate $2.5 billion in revenue this year. To gain a foothold in the West, GREE acquired U.S. mobile-game maker OpenFeint last year. The company's success has turned the boyish Tanaka into Asia's youngest self-made billionaire. Tanaka says he grew up obsessively playing NES games into the twilight hours. His parents thought he was wasting his time, he says. Clearly they were wrong.

--Matt Vella

  @FortuneMagazine - Last updated October 17 2012 05:11 PM ET
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