>Seems to me it would make more sense to omit the Newsgroups line and to
>have Netnews add it, using the default 'bit.listserv.listname'.  The PSU
>Netnews implementation does this; perhaps the PUCC implementation does
>not (does anyone know?) and that is the reason the Newsgroups default
>lines are being added.
>
>If the Newsgroups line were omitted, this would make it easier if there
>were ever to be a massive renaming of Netnews/Listserv groups or if
>individual groups were to be renamed.
 
When a Netnews DVM gets a reader file from a Listserv, it needs
some way to figure out what newsgroup the articles belongs in.
Having the Listserv list add the appropriate Newsgroup header is
one way to do this mapping; PUCC happens to use that method.
 
There are other ways to do the mapping.  You can look at the
file's tag;  usually the originid/fn/ft/dist/form are distinctive
enough to help you with the mapping.  Or you can look at the
Sender header.
 
If you use the SENDER header, you may find that the address in
the header changes over time.  That's because your Listserv
subscription may move from one peer to another if the peers
change or if the network topology changes enough.  When your
subscription moves, the node part of the address will certainly
change.  (The userid part of the address can also change, since
peered lists may have different names on different Listservs.)
True, this doesn't happen often, but if you are gatewaying a lot
of lists, it does mean you'll probably lose some articles
until you catch the change.  Increases maintenance time
on the Netnews side, too.  Also, there may be *some* mailers along
the route that munge the Sender header so it no longers looks
like what you expect.  (I'm no mail expect;  I don't know if this
*should* happen.  I just know that it *may*.  You won't find
mailers munching on the Newsgroups header, since they usually
have no idea what this header is for.)
 
If you use the file's tag, you may also encounter the same
problem.  Generally you can look at the fn/ft/originid/dest/form
and figure out that the file is from a Listserv and belong in a
particular group.  But the pattern that shows up in the tag can
change if your subscription happens to move from one Listserv to
another Listserv.  Until you catch the change, you can lose
articles....more maintenance time.  I've also seen the tags
change as a result of passing through some systems, say when the
file goes through some sort of gateway.
 
So the upshot is that there are at least three workable ways of
establishing the Listserv mail -> Netnews newsgroup mapping.
 
tried the tag method when developing PUCC's gatewaying, but
wasn't happy with the problems I described above.  I then moved
to the Sender header method, but it too had problems.  As a
result of discussion a few years ago, Eric Thomas added the
Newsgroups header to Listserv.