Proof-of-Mail? Like E-mail? I am not really convinced about this. I mean nowadays who is using e-mail to communicate? Nowadays almost everyone is using Facebook chat (Messenger), Discord, or any other instant messaging application. From the practical aspect, it would be much better to build something on instant messaging. Of course this is just/only my opinion about the industry, and I wish all the best with ListNerds and with everything else.