Suppose Signal generates a one-click (or even temporary) link. I can share that link that'll connect. That can accomplish the same thing as a signal.me address. Onetime links are definitely a thing. I'm sure people that know more can share even more creative ways to accomplish this. Someone has to have some fancy ZKP method for initiating contact.
> Perhaps what you want is a single buffer account
I think I covered this in my "infinite accounts" above.
> [1]
Seems to be more easily solved by letting me specify a handle at the per-chat level.
> Nothing stops you from creating the username NYT_Whistleblower, but that won't be what the NYT advertises to potential whistleblowers.
Seems you're passing the buck. Making it a "not my problem" issue and I think this is a big enough problem that it would make platforms like NYT wary of using such a system.
How? So you've got your account with a display name of "NYT_Whistleblower". Now... how does somebody else find it by accident?
That's easy; you want an internal identifier for Signal accounts that is unrelated to display name. This is already routine in most places including Discord.[1] Nothing stops you from creating the username NYT_Whistleblower, but that won't be what the NYT advertises to potential whistleblowers.
> Alternatively, if I have a username "not_godelski" then how do I get in contact with someone on HN while maintaining anonymity?
Well, you can't. Revealing your identity necessarily involves losing your anonymity, and I don't understand how you think those two actions could be theoretically separated. If you want to share your Signal identity with someone who only knows you as "godelski from HN", then once the sharing is accomplished they will know that "godelski from HN" and "godelski from HN's Signal username" are the same person. So will anyone who was allowed to watch the sharing.
Perhaps what you want is a single buffer account, where you tell people on HN to contact your buffer account (openly identifying it with yourself), and then you use the buffer account to reveal the identity of your actual account?
[1] Note that there is a tension between having a unique identifier by which Signal knows who you are, and the need for participants in two group chats not to be able to notice that your two usernames in those two chats belong to the same person. Discord is failing at this. To be part of a group chat at all, someone is going to have to have an identifier for you; if you want to maintain cross-chat anonymity, you'll need to be able to generate disposable identifiers that you can give to chat admins.