Craig Newmark has put together one of the most revolutionary, popular and well-thought out communities on the web. It's 1996 style design has not inhibited growth, but rather allowed the community to flourish and the largely free model has created a competitor for Monster.com, Careerbuilder.com and nationwide newspapers.

Recently, Craigslist added something of a site zeitgeist with a job board comparison page, and a Craigslist fact sheet. It's worth reading both of these, as well as Craig's blog to help understand how the power of free and easy has revolutionized the world of online classifieds.