Computer scientist Tony Hsieh made millions off the dot-com boom. But he didn't make his mark until he built Zappos — a customer service company that "happens to sell shoes." Now Zappos is worth over a billion dollars and known for its completely unorthodox management style.
Ridesharing wasn't a thing 12 years ago when John Zimmer was in college. But a class on green cities got him thinking about the glut of underused cars on the road, and eventually led him to co-found Lyft, a company that has helped make ridesharing a way of life.
Richard Branson took a record shop and built it into a label, a bank, an airline, space tourism, and 200 other businesses — all under the name Virgin. But the serial entrepreneur has also had his share of failures.