communities themselves are a criteria, message types can be a criteria (easier if you make a tag to mark them, this is the mechanics of filters)
and sometimes you need to turn them off, either permanently or temporarily, permanently tends to a be a bad thing for work but not giving the option is also bad (probably the compromise is to have a field with "specified time period" so you can put a year on things if you are really sure you don't care
also would be important to stash this data on the relay for you to retrieve in an application specific data blob