On 11 May 1999 00:10:35 -0000, D. J. Bernstein wrote:
>Let's say a user clicks the ``unsubscribe'' button while he's looking at
>an old message from the SOS mailing list. What should the MUA do?
>
>RFC 2369 suggests that the MUA follow the List-Unsubscribe instructions
>in that message. But what happens when the instructions are out of date?
You are arguing against the MUA support as suggested in rfc2369, but
for the MLM support as suggested in rfc2369. I'm arguing for MLM
support.
>What the MUA should do is find the most recent subscription confirmation
>from the SOS list, and follow the instructions in _that_ message. This
>is why I proposed putting a List-ID field into every message; it lets
>the MUA reliably keep track of the latest information for each list.
List-ID is a good idea. I don't know if
http://www.within.com/~chandhok/ietf/listid.shtml is your exact
implementation, but that one seems reasonable and is progressing
towards an rfc. The MUA still needs info from the MLM on how to
implement "unsubscribe". It should come with posts, as the info may
change. The WELCOME message to the list alone is not sufficient for
this reason.
>The RFC 2369 List-Unsubscribe syntax might be tolerable for confirmation
>messages. But there's no excuse for MUAs to assume that List-Unsubscribe
>appears in _every_ message. The MUA support envisioned in RFC 2369 is
>not the right thing to do.
Then you need a system to notify the MUA that e.g. the list address or
syntax (maybe even MLM) has changed. Unnecessarily complex and not
perfect. Subscribe under a new address, then unsubscribe. The new
address is unsubscribed. Not what you intended. It's cheap for the MLM
to include the info with every message. Of course, a MUA designer is
free to implement a more complex scheme.
rfc2369 says that the info _should_ be in every message. IMHO, it
suffices to do it in distributions, as per ezmlm-0.53 DIR/headeradd.
General VERP support would allow the MUA to extract it from the
envelope sender. However, qmail could provide a mechanism to make such
info available within the boundaries of rfc2369 (e.g.
ftp://ftp.id.wustl.edu/pub/patches/qmail-verh-0.02.tar.gz). With this,
we no longer have people that need help to unsubscribe (even without
rfc2369 supporting MUA). I doubt subscribers use info from old
messages, since it's the new ones that remind them that they want to
unsubscribe. The only questions we get are how to "see headers" and we
answer only that one. rfc2369-support in the MUA would eliminate also
this problem.
-Sincerely, Fred
(Frederik Lindberg, Infectious Diseases, WashU, St. Louis, MO, USA)
