I don't know. I think it would be pretty cool if people on our /f list could send us mail that we can open and read when we get online. A while back I was on a minecraft server that did this, where you could use a command to send mail to someone with a message, and then when the person came online they could open they mailbox with another command and read it, and see who it was from. The difference here is that only people on your f list could send mail, besides maybe staff? It would be a good way to send messages to someone while they are away just in case you had no other methods of contact- maybe you are telling them that you are going away for a while, tell them some news, or just send silly messages.