I've used CL to sell stuff rather successfully. Also found some good deals on furniture and appliances.
That being said, the personals boards are the biggest mess I've ever seen. The casual relationships category has pretty much become a list of hookers trying to line up johns. It's a race as to how many posts they can put up before people start flagging.
I've met a couple of ladies who took great glee in describing themselves in ways that no way matched their actual appearance, unless one took great literary license.....
Ciao