I recommend to reduce the amount of noise on the list, we adopt two simple rules, which can be automated so that no one need moderate the list.
A potential problem with this is people who use multiple email addresses (like me, but not to this list:) would be able to circumvent this rule. I think list-owner intervention might stop this, though I would hope list members would obey the rule without such.
The second is a limit on the size of each post. This enforce trimming posts, so that members don't quote the whole post, but only the part they wish to respond to.
I also suggest that if we do plan to adopt either or both of the above rules, we do so for a probationary period just to make sure that list quality and participation don't drop. I wouldn't want to make the list barren by enforcing such rules. A probationary period of one month might be good, then we can poll members to see if they think quality has gone up or down.
Cheers!
Daniel Ust
P.S.: Someone might have suggested the above before, but, if so, I do not mean to steal her or his ideas.