I agree whole-heartedly with Ben and LSoft on this!

Where this is the list owner's discussion list, I'd like to add that several of my large lists are owned by people that don't have the experience to be configuration owners and so I, as site admin, haven't given them the configuration owner ability.   

So for those lists we do something slightly different, but using the same features Ben mentions.  Those lists have:

• default-options= nopost
• send= private,confirm

This means in the first case that no new subscribers may post.  In the second case, it means that only subscribers may post.   To allow someone to post means the list owner examines their subscription and removes the nopost attribute.  Works flawlessly for us.

One caveat ... while I believe someone that posts to a list should be subscribed and receive distributions, not everyone in my real world agrees.   In those case, the poster still gets a subscription, but the subscription has nomail set.