Funny they pick out Craigslist, who as far as I'm aware, use OpenStreetMap because clearly Google maps doesn't work for them (cost presumably).
I worked on the map feature while at Craigslist about 6 years ago. Launching this on their own servers at the time (vs using Gmaps, which was the obvious choice) was a serious and important technical feat.
The decision to use OSM (as far as I remember) had to do with supporting open source (The company made a donation to OSM right after launching), keep user data within its servers and (as a distant third reason), keep the style more homogeneous with their layout.