I'm a dinosaur from a time when people actually spoke to each other personally or on the phone.
I find it frustrating exchanging endless chains of sms messages, often 20, 30, 50 or more about an add I have placed when the issue could be discussed in a 5 minute phone call, but many such exchanges lead to sales so you have to do it.
I too have never been scammed and can usually spot one from their adds, I have found a couple using my photos, but I am mostly selling, rarely buying from someone I don't know.
I have noticed that obvious scams, exotics etc on RDU have been left there for a while, I have not made a big deal out of it as they may be cooperating with authorities to trap some of the scammers. Maybe it just reflects a lack of supervision at the moment although they are prompt to process payments for featured adds.