> if people pay for the privilege of commenting, they will feel entitled and less likely to self-moderate

Not if getting banned means they have to buy a new account to post again.

Yeah, this is the something awful forums model. It's not perfect but better than most places.

Metafilter does this. It's surprisingly effective.

I think a notable exception to this is comments on the wall street journal. They are typically well-informed professionals having reasonable opinions who take the time to write in-depth comments -- not unlike this site, I suppose. And of course commenting is gated on having a paid subscription to the magazine, and I believe there is an additional paid membership that gets ones comments promoted.

I don't know if things are still like this though -- I haven't had a subscription for several years.