Craigslist
The Craigslist is a free classified advertisement forum founded in 1995 by Craig Newmark for the San Francisco Bay Area. There after it were expanded approximately 450 cities all over the world as of 2006.
Craigslist serves over 5 billion page views per month, putting it in 34th place overall among web sites world wide. The Craigslist is the leading classifieds service in any medium.