Just like they try to keep the facade up that CL barely makes money. They are swimming in so much $ it's insane.
They're profitable alright, but let's not kid ourselves that they have by choice left a LOT of money on the table, which is why all these value-added services are trying to take a share of the CL-pie.
I suppose we do have some estimates for their revenue, but not how much profit they actually make.
http://www.businessinsider.com/2011-digital-100#10-craigslis...
http://articles.businessinsider.com/2011-10-07/tech/30253426...