It seems to me that 2 list headers, in particular, are not used enough.
 
Mail-via= Distribute
 
Should be used whenever the list has the potential to have non-local
subscribers. "Distribute" is the same as "Dist2" as far as I can tell.
This should be done right at the outset when the list is created. It
seems to me that people have a tendency to look at "peering" the list far
too quickly without using this option (perhaps because peering is
emphasised in the documentation).
 
Service= Local   or   Service= (area1),(area2),...
 
(where Local is defined in your LOCAL SYSVARS file). Then use the value
"Service" as the "access level" in any of the following headers as
appropriate: Review=, Send=, Confidential=, Notebook= (4th parm). We
all see the number of TEST LISTs on the network and this can be avoided
by using these values properly. In addition, there are a number of
"local redistributions" (not peered) of many of the popular lists. These
lists should not appear in the "list of lists" and can be suppressed
with "Confidential= Service"
 
On 13 Apr 90, Mark Williamson at Rice posted a list of LIST keywords and
their default values for 1.6d on this list. I find this really useful
information and would love to see it updated for 1.7a - my impressions
are that the defaults listed in this posting are still correct.