Andrew,
Rather than seeking generic arguments about the merits and features of
listservers, I suggest that you simply imagine that an appropriately
selected "brand" of listserver software will allow you to get together
continuously, with little cost and little refractory period between
communications, into an ongoing, focussed, discussion of any topics you
collectively wish to discuss. You will further be able to archive all
discussions, and any related documents (which might not be distributed
but simply be made available to the discussants who wish to get them),
and you will be able to manage the list, including allowing the list
discussants to manage some features of the list each to their own
liking, with little overhead or cost to the list manager/owner.
 
Now, having imagined that scenario, the thing for you to do is draft a
proposal which describes, not _how_ people can get together to discuss
their favorite topics, but _why_ it is important for them to get together
(via email) to do so. And, remember, if anyone wishes to argue that a
goodly number of potentially interested persons do not have email and
would be left out of the discussion, this is not the case. If it is
important to communicate this topic to all interested parties, you (and
your discussion list-participating colleagues) can develop a periodic
paper summary of the discussions for distribution by more traditional
means. That would be no different than if you weren't to have made use
of the online list at all (except that you will now have lots of
electronic text available to more easily create the paper newsletter).
 
What is important regarding the listserver is to be careful to select
a "brand" that is robust, full-featured, and well-supported. A premier
example of this is LISTSERV on CMS by L-Soft, which underpins many lists,
such as the one to which you submitted your inquiry. When L-Soft brings
up the database portion of its LISTSERVices on other computer platforms
than CMS, such as Unix, then it will be outstanding under those
operating systems as well.
Cheers,
Peter