Green had the inspiration for Zimride after sharing rides from the University of California, Santa Barbara campus to visit his girlfriend in Los Angeles. He had used Craigslist’s ride boards but wanted to eliminate the anxiety of not knowing the passenger or driver. When Facebook opened its API to third-party developers, Green said he thought "Here’s the missing ingredient." Zimride linked drivers and passengers through the Facebook Connect application. By using Facebook profile information, student drivers and passengers could learn about each other. Zimride eventually became the largest carpool company in the United States. Green was introduced to John Zimmer through a mutual friend and the pair initially met on Facebook. The company name came from the country Zimbabwe, where, during a trip in 2005, Green observed locals sharing minivan taxis. Zimride launched at Cornell University, where, after six months, the service had signed up 20% of the campus.