All the talk about encryption and privacy seems to ignore this basic point. Association can be dangerous and this does not protect people from exposing themselves in that way.

True, but to be honest I am not sure that alone is worth 22B, in particular when you have to show shareholders how you plan to make that money back.

http://www.bloomberg.com/news/articles/2014-10-28/facebook-s...

My workaround for this is to create a group chat. I only talk to two people on Signal but I've asked both of them to message in the group chat that I've made. Now, I can answer chat messages on my nexus 5, nexus 6, and nexus 7. (I built the apk from source for the Nexus 7. I wouldn't recommend this if you actually want secrecy. I'm not doing anything confidential so I am not too worried about targeted attempts.)

Each device has its own key. Before a message is sent, the client grabs all the keys for each device associated with the account of the recipient, it then encrypts the message separately for each device and sends a separate encrypted copy for each device.

This scheme has various weaknesses, eg. a rogue key could be associated with someone's account without their knowledge, and anyone who sends this person messages will therefore be sending a copy encrypted with the rogue key.