Richard Damon writes:
Mailman, the manager for the mailing list doesn’t offer any such option. The closest that could be done is if a topic just goes on too long, a filter could be added to the list configuration which holds for moderation messages which match the subject. The problem is that if someone changes the subject slightly, it might not get caught by the filter depending on how detailed the filter was.
I'm -1 on both moderator-driven closure and time-driven closure (ping me if you care why ;-). That said, Mailman is a Python application and the extension interface is basically "derive a class from Handler or Rule with a method named 'process'." This kind of thing requires very little Mailman expertise (and I assure you the Mailman devs care a lot about Python: if the moderators want you to implement this, we will help). Regarding filtering on the subject, that's not how threading works. If you want to filter on subject as well as close the thread, fine, but the chance that someone accidentally changes the subject and it slips past the filter is very small. Most likely it's a deliberate attempt to either maintain context for a new thread, or evade the filter. Even if the latter, detecting such is still most cheaply done by humans, unless you're Amazon scale (Japanese news analysis today reported that Amazon proactively deletes reviews that its "AI" judges to be inauthentic or generated commercially).