>>mikece+(OP)
Support for Signal development supports all privacy-oriented software and systems, because Signal is open source.
The Signal Protocol already is an industry standard. What other Signal development - either the components, the code, or the concepts - are used by others?
>>wolver+nt
The only issue I'm aware of is that The Signal Protocol is only really defined in Signal's GPL'd code. So it's almost impossible to write a clean room implementation (e.g. Wire tried and ultimately failed. they ended up also GPL-ing their library).