In some games that I have played previously outside of TBT, any killing roles - Be it a vigilante, jack of all trades, mafia, or a serial killer for example - Can leave a message on the body of the victim they've killed that night that is then revealed to everyone once morning comes. (It only works if the kill is successful and goes through, of course!)
This works especially well in games with Last Wills and hidden Role Lists, and the messages left behind are of course anonymous. It's a way for the 'killers' to communicate with the rest of the players in the game in a very discreet way, forwarding information, taunting a player or team, and of course also commonly used by scum to trick the townies and provide them with false truths and misdirections. It adds another layer of deception to the kills because you can sometimes make another player look very suspicious by pretending to write just like they do, and things like that.
Sounds pretty interesting, I'll think on adding it in. Right now I want to see how sign ups go, if we don't break the twenty by Wednesday I'll just have to put the game on the backburner until next Wednesday.