Craigslist is a classifieds website with sections devoted to jobs, housing, personals, for sale, items wanted, services, community, gigs and discussion forums.
Craig Newmark began the service in 1995 as an email distribution list to friends, featuring local events in the San Francisco Bay Area. It became a web-based service in 1996 and expanded into other classified categories. It started expanding to other U.S. cities in 2000, and now covers 70 countries.
In March 2008, Spanish, French, Italian, German, and Portuguese became the first non-English languages Craigslist supported.
Downsides : It looks like they have no idea about design and whats appealing to the wider customer base. Their sites are the most basic as they com and they dont offer any sort of customer service or special features/promotions to enhance Ad conversion. It was just great timing for the founder having established these sites where the demand was high, but they have since changed very little in regards to their site layout or service.