Found at http://archives.postgresql.org/pgsql-general/
If you hate getting many mail messages per day then you should consider
a digest (where you receive multiple messages to the list as one message
to you). To subscribe or unsubscribe from the digested list, send mail
to majordomo@postgresql.org <mailto:majordomo@postgresql.org>. The body
of the message should contain the single line "subscribe-digest
pgsql-general" or "unsubscribe-digest pgsql-general"
Good advice, bad instruction. If you send the aforementioned command to
majordomo@postgresql.org, it is rejected. The correct way to get the
digest is:
1. Subscribe to the list normally.
2. Once subscription is complete, send majordomo the command "set
LISTNAME digest"
It's also worth doing a "help subscribe" and a "lists-full LISTNAME", so
that you can see what options are available for the digest delivery.
Anyone who doesn't know how to use majordomo's "help" function is likely
to become very frustrated by the fact that the website's instructions
don't work.
BJ