Entrepreneurs to Watch in 2013

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Oliver Samwer
Rocket Internet

Like him or not, Oliver Samwer is changing competition online. The self-proclaimed "most aggressive guy on the Internet" creates nearly-identical versions of U.S. sites (Airbnb, GroupOn) and brings them overseas before the original company can. Some start-ups partner with the German entrepreneur, others fight. But in 2013, any successful web entrepreneur will have to reckon with him.