100% waste of time.
Posted my wife's car for sale on Autotrader. After 6 months, I received a total of ZERO contacts from actual buyers. Oddly, I was contacted several times by scammers who all used the same old pitch -- they wanted to buy the car but they were out of state so could they send me a check that included money for shipping and then I just needed to give cash to the shipper...blah blah blah. I eventually just sold the car to a dealer. Completely wasted my time and money with Autotrader.