[Mailman-Users] "topics"

[bergenpeak at comcast.net]

I dumped out a list config and noticed at the bottom some config around "topics".  Some of the comments in the text suggests that a list subscriber can "choose to only receive messages from the mailing list for a particular topic bucket (or buckets)".  

Is this saying then that there's a way for users to see only a subset of messages sent to a list?  Is this configurable from a users perspcetive?  That is, when a user subscribes, is there a way for the user to indicate in the subscribe message the regular expression to use to determine which messages (buckets) they're interested in?

thanks