In 2007, a cash-strapped Brian Chesky came up with a shrewd way to pay his $1,200 San Francisco apartment rent. He would offer “Air bed and breakfast”, which consisted of three airbeds, breakfast, WiFi and a desk to work, to attendees of the Industrial Design Conference, who needed a place to crash over the weekend. After an initial period of uncertainty, in which the founders sold Barack Obama and John McCain cereal to sustain the business (seriously), the company received $20,000 in see...