[william-newman]

It is not sufficient simply not to target growth. But not targeting growth removes what is otherwise one helluva tough design constraint for a filter system. Imagine writing a spam filter when you're being paid by beancounters whose bottom line is maximizing the number of messages. Even, sometimes, beancounters who face strong temptation to maximize the number of bytes of email this quarter and worry about the longer-than-a-month-term consequences later.

Also, some kinds of filtering (and related things, like informal community norms) don't scale, so if the community hasn't grown too much, the problem might tend to be easier. Hacker-oriented mailing lists with 100 posters don't seem to be too hard to moderate, but I'm not eager to try 10,000 posters.