I was thinking about this for quite some time in late 2017. Being aware of all the cons, I badly wanted to forget about it. But in the end I could not walk away from the idea.
On the one hand, it seems like plain abuse of the functionality. On the other hand, it is such a cool and different way to use the technology, and who knows where it may lead.
For example, you could have a central authority (that you set up and control) providing confidential info to your other (future) automated systems (and you don't even need to reveal the location of your authority to your clients, and vice versa).
Or you could have automated authentication for logging into websites. For example, you provide the site with your public address, the site server sends you an authentication token (encrypted) in the memo, you provide it back, proving you are really you. Forget about storing passwords.
I think the list of possibilities is endless. As is the list of potential for abuse :-/
Anyway, I made a proof of concept, which works on the Testnet and can be found here: https://hmatejx.github.io/Interstellar-Whisper/
