Free services like Craigslist have decimated the classified advertising departments of newspapers, some of which depended on classifieds for 70% of their ad revenue. Research has shown that Craigslist cost the newspaper industry $5.4 billion from 2000-2007.
A bank robber hired decoys on Craigslist and escaped down a creek on a Inner tube.
There is a strange subculture of Craigslist art, which involves artists posting offbeat requests on craigslist and seeing what happens. Some examples:
Kenneth Tam offered cash to any couple who would let him observe, and film, an ordinary dinner in their home while he sat, silent, in the background.
A California teenager traded up an old phone on Craigslist for different items until he eventually acquired a Porsche.
A bank robber escaped the scene of a crime by arranging (via Craigslist) for a dozen identically dressed and unwitting civilians to be standing at the exact place and time of the arrival of the armored car he intended to hijack.