The 2009 TIME 100

The culture of the internet, at its best, involves people working together to make life better. Sometimes called cooperative capitalism or social entrepreneurship, it is practiced every day by millions of individuals and a small but growing number of for-profit companies. For years, Robin Chase, a co-founder of Zipcar, has run such a business, in which people share a community-based pool of vehicles. Customers use Zipcar, which rents cars by the day or hour (when public transportation won't quite do the job) and makes smart use of technology like GPS to connect people with autos and trucks that are parked near them.

The Zipcar operation recognizes that people are fundamentally trustworthy. If you trust your customer community, they'll respond by operating in a trustworthy manner, self-policing your operation. Zipcar's success fuels the whole Internet-based sharing culture, and Robin, 50, also uses social media to get car-sharing fans to work together in communities. This implicitly pushes the sharing culture to even more people.

In Robin's new venture, GoLoco, people work together to ride-share. GoLoco helps friends, neighbors and co-workers figure out who is going where and matches them by need. The riders split the cost of the trip. GoLoco manages those payments fairly and easily. It's a simple system, and it works, which is key to successful Internet efforts.

Robin's work illustrates what's best about people using the Internet: not well-intentioned yet futile do-goodism but business that's also a community service. It's about people using the Internet to work together in the service of one another. I hear a guy got elected President as part of this movement.

Newmark is a customer-service rep for and the founder of Craigslist

Fast Fact: Chase's formula: 1. Identify a need 2. Build a platform to share and satisfy the need