Craigslist is a popular website that allows users to post classified advertisements across many categories like housing, jobs, items for sale in over 450 cities worldwide. 30 million Americans use Craigslist each month to find housing, jobs, and other goods and services. Originally starting as an email list among friends, Craigslist has grown significantly to serve over 570 cities in 50 countries by 2009 while maintaining its classified listings as a low-cost alternative to newspaper classifieds.