[Mailman-Users] Understanding patterns of unsubscribe

Steven D'Aprano steve at pearwood.info
Mon Dec 22 23:53:13 CET 2014

Hi all,

Back in September, I migrated an announcement-only mailing list from 
Yahoo to mailman, with approximately 1800 email addresses. An unknown 
number of these were dead.

The mailing list I am running sends out one, maybe two, emails a month, 
at around the same time of the month. It's not a discussion list, so 
there are no replies from subscribers.

I expected that the first month, there would be a lot of automatic 
unsubscriptions, as the dead addresses were noted and removed, and then 
in subsequent months there might only be a trickle of automatic 
removals. To my surprise though, there has been a steady pattern of mass 
unsubscriptions each month, around 100-200 each month following the 
posted announcement.

I'm not sure whether this is normal (if it is, unless the number of 
unsubscriptions begins to fall soon, I'll soon be left with no 
subscribers) or whether I'm doing something wrong.

Here are my bounce processing settings:

bounce_processing = Yes
bounce_score_threshold = 4.0
bounce_info_stale_after = 65
bounce_you_are_disabled_warnings = 3
bounce_you_are_disabled_warnings_interval = 10

Remembering that I only send out 1 or 2 emails every 30 days (give or 
take a couple of days in either direction), does this seem reasonable? 
Or is my bounce processing too strict?

Thanks in advance,


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