@briankrebs Decentralized https://simplex.chat/ does not even use user ID's. You create and dispose of addresses as you want. It is easy to use, but most people are too habituated to Signal or other apps to try it. Here is my current address: https://simplex.chat/contact#/?v=1-4&smp=smp%3A%2F%2Fh--vW7ZSkXPeOUpfxlFGgauQmXNFOzGoizak7Ult7cw%3D%40smp15.simplex.im%2FJfQo6pHMEXsSkJKXL83pinIq6CddTEK5%23%2F%3Fv%3D1-2%26dh%3DMCowBQYDK2VuAyEAUzwMM2xx8T2yqOQxY3jysgaFAqL8ZmVJWFIX30JVH0U%253D%26srv%3Doauu4bgijybyhczbnxtlggo6hiubahmeutaqineuyy23aojpih3dajad.onion

https://getsession.org/ uses the Signal protocol with user names and is decentralized. Matrix and XMPP are also good.