What I have not seen mentioned so far on this is that the "subject tag"
does not have to be the full userid of the list, it can be an abbreviated
form to save space in the subject line of distributed list postings.  When
I set the subject tags up for my lists I did a brief poll, and the vote
was for an abbreviated form (they had the choice of the full thing or *my*
short version).  So, for example, the subject tag for AUTOCAT is [ACAT].

All that takes is to insert the line in the list header, thus:
* Subject= ACAT

Then those who want it change their hearer option to SUBJECT.
If you want it as a default for new subscribers put SUBJECT in
your default-options field.

If I recall correctly, this is the same as the FULL header option, plus
the wrinkle of the SUBJECT tag.  That means that there is going to be a
little more demand on resources compared to the standard default
header of SHORT.

Whatever, if you are going to have that tag available for those who
want it can be whatever you wish, just edit your list header.

Douglas