I thought of a completely trivial way for #Mastodon to implement all their soft security stuff w/o content leaking when it federates to incompatible servers.
It's such an obvious idea that I can't help but wonder if @Gargron is already doing it...
The idea: Put sensitive content in a non-standard XML element (e.g. <scopedcontent> instead of <content>). Poof, the problem just goes away, until a node is actually malicious.
@JollyOrc @HerraBRE Whether a follower is from a server that doesn't understand privacy, or willfully ignores it, there is no way to tell. I have considered the "using new tag" or even Base64-encoding idea, but I think it just masks the issue. The real solution is that you should be aware who you allow to follow you, if you want your follower-only privacy to be respected.
I agree: The system should, where feasible, give people some sort of indication if it detects followers from a "bad" instance that doesn't conform to the standards.
Of course, that cannot solve human malciousness or other PEBCAK issues. And we probably really don't want a codified reputation system...