Craigslist is a classified advertisements website that started as a local newsletter in San Francisco. It has since expanded to over 450 cities worldwide. Users can post housing, jobs, items for sale, services, and personal ads. Craigslist monitors content by allowing users to flag interesting or inappropriate posts. Each city has its own Craigslist site focused on that local community. Craigslist incorporated in 1999 and has grown into a successful business, working to prevent scams while expanding its reach.