What it is: In-Game CoD mail.
How to:
Make yourself letters by using this from a character and sending it to your appropriately named character (Tirion, Fordring, Crusader, Icecrown, Rewards, etc, anything that fits your theme):
/run SendMail("NAMEHERE", "Argent Tournament Rewards", "Your dedication to eliminating the scourge will not go unheeded! Please keep this thank you note as a reminder of your heroic efforts in Icecrown!")
This goes from your one anonymous alt to your named alt (that people will see the name of both, one as the sender, one as the creator, although you can go around this and send it from your named alt to another, return it, then resend it again but that's alot of effort).
Copy this:
/run SendMail("NAMEHERE", "Argent Tournament Rewards", "Your valiant efforts in the Argent Tournament have not gone unrewarded! We have a thank you letter from one of your fans!")
Go into your Social Tab (Default: O), and look in the Chat Tab. Find a name (I suggest going alphabetically). Take that name and put it into your macro. Insert one of your "Plain Letter" from earlier into that mail and send it out, CoD for whatever you think is appropriate (Don't go crazy, like over 100g, not enough people will take it). Best part is, even if someone doesn't take it, they just send it back so you don't have to make more letters.
It takes 1 hour for mail to appear in mail boxes, so you have to wait 2 hours before you'll see anything. Just log in, send mail, play the game and the next day or even in a few hours check again to see if you have any bites.
Enjoy!