Would you consider transitioning this list serve to the system dynamics society board? It's still members only and could be moderated if need be. Bob Eberlein has already added a number of the special interest groups and it would be a great way to make sure that SD content isn't too fractured. It would also be easier for new potential contributors to find it. You also get the benefits of thread organization and archiving.
I realize it would take some doing on the part of members of this list to get signed up, but it really isn't too complicated and Bob has added some posts that explain how to get email digests of only the posts you are interested in. I hope folks check it out and sign up regardless. Diversity is great and healthy for the field, but consolidation of the content can have tremendous benefits.