I may be mistaken, what I've heard is rumour and telling it violated someone's NDA, but I think the burden of proof is on your side. Consider Signal, since tha

I may be mistaken, what I've heard is rumour and telling it violated someone's NDA, but I think the burden of proof is on your side. Consider Signal, since that's in the subject. Despite having my phone number on several web sites, I don't get spam on Signal, which I take to mean that the Signal maintainers are successful at fighting spam (and it doesn't matter whether they do so mostly as server operators or protocol designers). If you wanted to persuade them to interoperate/federate, then you have to provide arguments, ie. the burden of proof is on you. Saying "none of the well established networks have yet solved the problem" isn't enough, because you'll be trying to persuade someone who has solved the problem. You could try to argue that spam is a worthwhile price to pay, or that it could be fought as well using your protocol as via Signal's own servers, or other things. What you can not do is lean back. An interop mechanism is a server-to-server bulk message delivery mechanism, and so far I've not heard about any way to do bulk message delivery that doesn't atttract the interest of spammers. That spammers would try to spam Signal users via the interop mechanism is plausible by default, just as it's plausible that spammers would try to spam Gmail/gtalk users.