I've sold things to real people on Craigslist, for cash. The scammers are easy to filter out, but I'm sure there are smarter ones out there whom I just haven't encountered yet.

They do warn you about scammers, and my feeling is that if they tried to filter out the vermin who say "my agent will arrive with a cashier's check to pick it up" the scammers would just find some way around it, and people would get a false sense of security to boot. Whack-a-mole games, in other words.

A site for discussion would be Discogs, where I've had almost nothing but great experiences: all nice, honest people. Maybe the fix for Craigslist would be to split into verticals, where a community could develop, something that's absent now.