One possible implementation is to scale the number of comments a person can make in a time period dependent upon his median comment score over some previous last time period.
I've got no citation at all, but I'd bet that people who have N comments left in the next week will be more miserly about using them. You could also make exceptions for replying to replies and that kind of thing, so as not to artificially limit back and forth (which is sometimes a good thing; for example, tcptacek and zedshaw always have good conversations, if a bit argumentative).
It'd cut back on people who shotgun "funny" comments and have them land occasionally without disrupting people who try to only comment when they have something valuable to say.
A set of super voters would also be good, but, again, not super democratic.
I've got no citation at all, but I'd bet that people who have N comments left in the next week will be more miserly about using them. You could also make exceptions for replying to replies and that kind of thing, so as not to artificially limit back and forth (which is sometimes a good thing; for example, tcptacek and zedshaw always have good conversations, if a bit argumentative).
It'd cut back on people who shotgun "funny" comments and have them land occasionally without disrupting people who try to only comment when they have something valuable to say.
A set of super voters would also be good, but, again, not super democratic.