On 02/03/2016 09:57 AM, Nicholas Barnett wrote:

If someone in both reply to it and create a thread, well, it becomes very tangled as B people don't see A messages and vice versa, but sometimes they see messages from AB people responding to stuff they haven't seen. B-listers may respond along the lines of a response already made on list A. Confusing!

(see note below)

Cross posting is an issue that will always cause problems because there is no single, right way to handle it. Consider an announcement to listA and listB with ListB in ListA's regular_exclude_lists. You want this to be a single post so members of both lists don't get duplicates. Yet, if people receiving the post who are members of only one of the lists reply-all their replies to the other list are non-member posts which may be an issue. This is in addition to the confusion that you mention.

One of our 60,000 has proposed that the original poster should post to the two lists in two separate emails, but could there be an option for each list moderator to select whereby if one addressee of a post is a list, then other addressees may not be? It would be bounced! (And the option should be the default, of course, so you'd need to opt out to allow multiple lists as addressees, and create tangled threads)?

Not allowing cross posting is a social issue. It can be enforced partially, but not completely reliably within Mailman. First of all, Cross posting with many of the issues you raise occurs with posts to lists that may be in different Mailman installations or even among lists not all of which are Mailman managed lists. Also, even with posts to multiple lists in the same installation, if Bcc's and aliases are allowed, Mailman can't always know if another list in the installation is a recipient of the post or not.

I think you can do as well as can be done with the following settings in current Mailman 2.1. In Privacy options... -> Recipient filters for each list, set require_explicit_destination to Yes (this is already the distribution default) and set max_num_recipients to 2 (you can make this the default by setting DEFAULT_MAX_NUM_RECIPIENTS = 2 in mm_cfg.py).

This will say that for a post to this list to not be held for moderation, it must explicitly address this list and must have no other explicit addressees (i.e. total addressees < 2).

Of course, this will preclude addressing other, non-list recipients in list posts unless they are Bcc'd, and will undoubtedly cause confusion of a different kind.

If you post this to the mailman-users@python.org list, you will reach a wider audience and may get more information about how other installations deal with this issue.

note: For the lists that I'm on, I see the opposite problem. People top post and quote entire threads, so the issue isn't people seeing replies to stuff they haven't seen, it's digests and archives being polluted with multiple copies of quoted and requoted material.

-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan

On 02/03/2016 09:57 AM, Nicholas Barnett wrote:

If someone in both reply to it and create a thread, well, it becomes very tangled as B people don't see A messages and vice versa, but sometimes they see messages from AB people responding to stuff they haven't seen. B-listers may respond along the lines of a response already made on list A. Confusing!

(see note below)

Cross posting is an issue that will always cause problems because there is no single, right way to handle it. Consider an announcement to listA and listB with ListB in ListA's regular_exclude_lists. You want this to be a single post so members of both lists don't get duplicates. Yet, if people receiving the post who are members of only one of the lists reply-all their replies to the other list are non-member posts which may be an issue. This is in addition to the confusion that you mention.

One of our 60,000 has proposed that the original poster should post to the two lists in two separate emails, but could there be an option for each list moderator to select whereby if one addressee of a post is a list, then other addressees may not be? It would be bounced! (And the option should be the default, of course, so you'd need to opt out to allow multiple lists as addressees, and create tangled threads)?

Not allowing cross posting is a social issue. It can be enforced partially, but not completely reliably within Mailman. First of all, Cross posting with many of the issues you raise occurs with posts to lists that may be in different Mailman installations or even among lists not all of which are Mailman managed lists. Also, even with posts to multiple lists in the same installation, if Bcc's and aliases are allowed, Mailman can't always know if another list in the installation is a recipient of the post or not.

I think you can do as well as can be done with the following settings in current Mailman 2.1. In Privacy options... -> Recipient filters for each list, set require_explicit_destination to Yes (this is already the distribution default) and set max_num_recipients to 2 (you can make this the default by setting DEFAULT_MAX_NUM_RECIPIENTS = 2 in mm_cfg.py).

This will say that for a post to this list to not be held for moderation, it must explicitly address this list and must have no other explicit addressees (i.e. total addressees < 2).

Of course, this will preclude addressing other, non-list recipients in list posts unless they are Bcc'd, and will undoubtedly cause confusion of a different kind.

If you post this to the mailman-users@python.org list, you will reach a wider audience and may get more information about how other installations deal with this issue.

note: For the lists that I'm on, I see the opposite problem. People top post and quote entire threads, so the issue isn't people seeing replies to stuff they haven't seen, it's digests and archives being polluted with multiple copies of quoted and requoted material.

-- Mark Sapiro <mark@msapiro.net> The highway is for gamblers, San Francisco Bay Area, California better use your sense - B. Dylan