[incompatible]

I'd put the fault with the smartphone + software industry for failing to come up with a shared open/secure messaging protocol, with fault also to governments for not insisting on such a protocol, and fault also on people who willingly use proprietary systems including WhatsApp and Messages with rejection of "green bubbles".

The current situation of competing proprietary non-interoperable systems seems ridiculous.

[mandelbrotwurst]

My understanding is that the Signal protocol is exactly that and is even used (or at least claimed to me used) by WhatsApp under the hood, although obviously we shouldn't take them at their word re: the details of their implementation / that they aren't capturing / collecting / sending user input before and/or after the "ends" of the "E2E", so to speak.

The issue isn't as much the lack of an open and secure messaging protocol as it is an inability to build a social network on an open client that is as large as the ones that private corporations have been able to build with their closed source solutions.

Their adding of additional features into their messaging apps that add both usability and complexity makes this an even more difficult barrier to overcome.

[charlesdaniels]

matrix.org seems very promising!

I've been using riot.im for some time and have generally been pleased with it.