@thaniusTobias Hellgren @mjg59Matthew Garrett Look into #XMPP.

Projects like Quicksy and Prāv use phone numbers and allow easy onboarding and contact discovery. Unlike Signal, there’s no lock-in - you can choose other servers which don’t need a phone number, or host your own server (for which see Snikket, which allows for easy hosting of a private server, and provides rebranded clients and easy invitation-based onboarding), and still talk to Quicksy/Prāv users.

Servers on the XMPP network are also smaller and less convenient targets for backdoors, corporate takeovers, lawsuits, DDoS attacks, etc than the centralized servers of Signal etc. And since you can self-host it, you can actually trust that the server is running the code it has published.

For more information, please read The Quick and Easy Guide to XMPP. And if anybody is thinking of sharing any OMEMO FUD from a certain Signal fanboy…read this first.
http://moparisthebest.com/against-silos-signal/