Craigslist

Craigslist is a centralized network of online communities for free classified advertisements (with jobs, internships, housing, personal advertisements, erotic services, for sale/barter/wanted, services, community, and pets categories) and forums on various topics.
Description.
The service was founded in 1995 by Craig Newmark for the San Francisco Bay Area. After incorporation as a private for-profit company in 1999, Craigslist expanded into nine more U.S. cities in 2000, four each in 2001 and 2002, and 14 in 2003. By September 2007, Craigslist had established itself in approximately 450 cities in 50 countries.
In 2007 Craigslist operated with a staff of 24 people.
Its sole source of revenue is paid job ads in select cities ($75 per ad for the San Francisco Bay Area; $25 per ad for New York, Los Angeles, San Diego, Boston, Seattle, Washington, D.C., Chicago and recently Portland, Oregon) and paid broker apartment listings in New York City ($10 per ad).
The site serves over nine billion page views per month, putting it in 56th place overall among web sites worldwide, ninth place overall among web sites in the United States (per Alexa.com on January 10, 2008), to over thirty million unique visitors. With over thirty million new classified advertisements each month, Craigslist is the leading classifieds service in any medium. The site receives over two million new job listings each month. So it is one of the top job boards in the world.
Nonprofit foundation.
In 2001, the company started the Craigslist Foundation, a § 501(c)(3) nonprofit organization that helps emerging nonprofit organizations get established, gain visibility, attract the attention of potential donors, and develop the skills and knowledge required for long-term success.
It accepts charitable donations, and rather than directly funding organizations, it produces face-to-face events and offers online resources to help grassroots organizations get off the ground and contribute real value to the community.
Cities.
The first 14 city sites were: (entire list )
Vancouver, British Columbia, was the first non U.S. city included.
London was the first city outside North America.
In November 2004, Amsterdam, Bangalore, Paris, Sao Paulo and Tokyo became the first cities outside of primarily English speaking countries.
In May 2008, 500 cities in 50 countries are represented.