Rather than censoring messages, I propose that this mailing list support free speech and encourage lots of different topics. All further discussion on the topic will go through the newly created communication path. The decision of when a topic is getting out of hand should be a consensual decision among the members of the particular network, to be enforced by the moderator. The people interested in the topic can then decide the best way to discuss their own interests, and manage their discussion. A human network is a springboard for human interaction and thus for human action.
Lets view it as such and keep repression and censorship at a minimum.
With regard to the Moderator's editorial comment about irrelevant discussion topics, I would like to suggest that if a topic appears in a large number of messages, one automatically assumes that that topic is of interest. Ideally, human-nets should have an index or table of contents so that readers can look only at what interests them. Alternatively, one of the sublists could be a table of contents. Presumably, each human-nets reader would receive all the sublists at once. Perhaps the subject field in the sublist would contain the specific subject area.