The server is also open source https://github.com/signalapp/Signal-Server

Am I mistaken or isn't there some way in which Signal effectively prevents anyone from running their own server? I seem to recall hearing this.

(I mean, there's the obvious practical problem that the official server URL is hardcoded into the app, so if you wanted to use your own server you'd have to build your own copies of the app for you and your communicants, but other than that...?)

A pile of separate Signal clones = zero interoperability = zero functionality. So that's why there aren't any.

You could solve that by Federating, except... Federation would be lovely if you could actually deliver Signal's goals and do federation for free, but what we always see from proponents of Federation is that was their goal and so they're done. Oh you wanted security? Sorry, we federated everything, so you'll need to get every single member of the federation on board with every single change you need, we know you can't get that done but that's fine because our priority was federating stuff, so we are successful, shame about your goals.

As an example, somebody earlier in this thread mentions you can "just" know who is communicating with who anyway. Signal got rid of that, because they can, and it's a security improvement, so they put all the work in and did it. Now even Signal's own servers don't know who sent most messages! "Sealed Sender" means Signal has no idea who is sending this message to my friend Steve. Maybe it's me? No idea. It just has to be somebody who Steve allows to send him messages. Could be Steve loves spam and so it's a spammer. Could be Steve loves the AfD and so it's a Nazi. No way to know without reading the message which only Steve's Signal client can do.

Now imagine trying to roll that out to a federated system. After years of effort maybe you switch it on, and then you find a bug and have to switch it off again for a few years while you fix that. Hopeless.

> You could solve that by Federating, except... Federation would be lovely if you could actually deliver Signal's goals and do federation for free, but what we always see from proponents of Federation is that was their goal and so they're done. Oh you wanted security? Sorry, we federated everything, so you'll need to get every single member of the federation on board with every single change you need, we know you can't get that done but that's fine because our priority was federating stuff, so we are successful, shame about your goals.

I have a lot of serious criticisms of Matrix, to the point where I don't recommend it to friends (yet?), but this feels like an unfair and unserious criticism. I don't think you can fault their motives.

And as another user points out, if Signal goes down in the United States because of legislation, so much for the supposed convenience of your non-federated central server approach! If that happens I'll take Matrix over nothing, thanks.

But conversely, if legislation really succeeds in killing Signal in the entirety of US (and EU won't be far behind!) to the point where they're forced to use geo-IP blocks, the end result is still strictly worse off.