A lot of the people discussing private messaging don't really understand what makes messaging private. The thing that makes messaging the most private is the *location* of the messages, and the *transmission* of the messages. The messages should preferably be stored on machines the sender and/or the recipient personally control, and on no other machines. Other machines, if included in the system, should only be used to forward/relay the messages, not to store them. And the messages should be obfuscated with encryption and sent over a secure connection. It is additionally best practice, if a bit annoying, to use different accounts with different devices. A protocol like #Cordn allows for single-device or multi-device logins, for convenience, but I am remaining with single-device, for the added security and the ability to block one device's account without losing access from the other (after losing a cellphone, for instance). The article above explains the final two aspects of private communications: forward secrecy and post-compromise security. HTH and GM