NNTP gatewaying trashes Message-IDs
when a message is relayed to NNTP, the NewsRunner unconditionally replaces the existing Message-ID with its own. this breaking threading when reading a list via news, and when an NNTP user replies to a list message.
a better solution would be either: 1) do not rewrite the message-id unless the NNTP server reports an error when posting it (duplicate ID); or 2) optionally, always rewrite posters' message-ids into a mailman-generated ID, and use this ID for both mail and news.
i have implemented the former at our site and it appears to work, but it's so ugly i'd not feel comfortable submitting a patch for it.