You could easily imagine many such experiments. What would it take, for example, to design a mailing list that was flame-retardant? Once you stop regarding all users as isolated actors, a number of possibilities appear.
Interestingly, I read this immediately after reading Webdiary’s attempts at resolving the flaming issue. They adopted a “five post limit” as an experiment to help reduce personal attacks.
I’m keenly interested in this issue as I expect we’ll have to have to deal with this sort of thing as we open up “talkback” tools on the WWF website. This won’t be for a little while to come, but I want to be well prepared and have some measures ready to apply before we launch.