Exactly.
The fake ads were just a minor annoyance, you could spot them before you even clicked on them 99.9% of the time. The dealers posting their auction shitboxes in the owner section was kind of annoying, but again, pretty easy to spot. No license plate, paper floor mats from the detailer, very brief description, and you could search the seller's phone number and his name was usually Mohamed Abdi or similar.
I've bought and sold several cars on CL, buying was typically easy and selling was usually a PITA. It's a double edged sword, that's just the nature of it, but a lot of the time it depends on what you're selling and the type of people that the car attracts. The absolute WORST was trying to sell a '95 Caprice. The tire kickers who wasted my time with that, my God what a headache. But sometimes you would get lucky and the first guy shows up on time and buys your car without any issues. Definitely hit or miss, again it's the nature of using a free service and dealing with the people it attracts.
Like Kerry said, you could find some gems because some people were incapable of posting a halfway decent ad which would scare off most everyone else, making it easy to get a good car/deal if you put in a little effort. Unfortunately, you'll have a lot less of that now with the $5 fee. Hell, it's only $5 but you know how people are.