There are 500 Craigslist sites in 50 countries and in each of the 50 U.S. states. Many local businesses have made Craigslist a part of their marketing mix, according to Bowling, who provides some tips for those who want to get in on the mix. It's important to use keyword-rich text in the title and description of the ads, she writes, because the site relies on simple algorithms that displays search results first by the posting date, with newer ads appearing above older ones, and then by keyword.