Filtering out unwanted messages

[rt121212121]

I suspect that unless a user can avoid receiving messages they do not want, a public mailbox where they can be contacted or interacted with, is problematic. Even if the server naively imposes a cost on an anonymous user posting a message to a channel, this does not necessarily mean that that cost to the server compensates the recipient for the inconvenience of dealing with the message. Is there a plan for filtering out unwanted messages?

[Danconnolly]

This is a good point. I'm wondering whether that would belong in this spec or whether that should be an extension that is defined in another spec. I would prefer this to be in an extension.

[rt121212121]

I agree it is off-topic.