Rocket Internet is one of the most successful - and controversial - startup incubators in the world.
Since its founding in 2007 by Oliver Samwer, and his two younger brothers, Marc and Alex, Rocket Internet has helped launch over 70 companies across 50 countries, generating a combined revenue of $4 billion.
Just last week, the Berlin-based startup accelerator raised $445 million at a $4.5 billion valuation. And it's reported to be shooting for an IPO soon, with hopes of reaching a valuation as high as $6.7 billion.
But as successful as it's been, Rocket Internet has also received a lot of flak for its strategy to copy ideas that work in certain markets and build the same exact business model in regions that haven't yet been explored - earning such nicknames as "copycat," "clone factory," and "scam artist," along the way.
But there's no question that Rocket Internet has built a massive business empire. Here are 15 of the biggest U.S. tech companies it "imitated" to get to where it is now.