I used cryptographic software as an end-user for many years, like GPG for instance, and agree that it's hard, and we need to train people to use correct security habits (infosec and opsec), to minimise exposure to hostile elements.
I've tought at cryptoparties and other events, I have spoken to many intelligence whistleblowers, some of which I consider to be close friends, and they've told me about some of the techniques used on the national intelligence agency level and how wrong use of crypto and general bad operational security practices can expose you. So while I'm not a trained cryptographer, and do not claim to be, I have extensive experience not only building secure software, but also, thanks to whistleblowers know about some of the ins and outs of the intelligence industry re crypto and surveillance.
An alternative needs to be as a bare minimum cryptographically secure. And then on top of that it would be very nice if there was federation, not tied to phone numbers and all the components being open source. Those last 3 points is where Signal fails currently. Federation is something that moxie tried, didn't work out, now he's basically not in favour of that, the phone number issue is of course well known, and the redphone server component is not open source.
Hits all your technical requirements. Setting up your own homeserver is cake. Federation is a key part of the core design. End to end encryption is just about to be finalized. History syncing between multiple clients. Bridges for pulling in other chat systems like slack and IRC. Completely open source. To me, this is the perfect messaging platform. Just needs some UI polish and I could see it really taking off. Had you seen this yet?
[1] https://whispersystems.org/blog/the-ecosystem-is-moving/
I recall e.g. that Moxie reviewed Telegram's security, found that none of it made any sense and that its authors didn't know what they were doing. https://tobtu.com/decryptocat.php looks like the cryptocat analogue of that. Have the two projects improved somehow? Have some people joined or others left?
Could you please also provide links for the claim that CryptoCat and Telegram are being used by governments to hunt down activists?
We now have two examples --- CryptoCat and Telegram --- of "secure messaging" systems being used by governments as a way of hunting down activists. Why do we need more? Can't the question be settled now?
As gently as I can, I'm going to push a little further. I poked around your site a little to get a sense of where you're coming from. Your post today opens up like this:
One of the things I do is cryptography and infosec training for investigative journalists who have a need to keep either their sources and communications confidential so they can more safely do their work in the public interest.
Can I ask what your qualifications are in training journalists in keeping their communications secure? Investigative journalists working in hostile regimes, even in smaller countries, are facing adversaries that are better funded than almost any other imaginable threat. Cryptography is incredibly hard. Elsewhere on the thread, you said "I'm not a cryptographer". Neither am I! I've spent the better part of 10 years getting decent at breaking cryptosystems for clients, and I still refuse to do privacy implementation work, because I'm simply not up to the challenge. Are you sure you are?