China's two-year-old Ofo becomes a billion-dollar startup 
China's bike-sharing startup Ofo has raised $450 million in Series D funding round from DST Global, Uber rival Didi Chuxing, and others at a valuation of over $1 billion. Ofo was founded only two years ago as a student project by a PhD dropout and four students. Every Ofo bike has a smart lock and its own unique number plate.