The Game Moderator (or just "mod") is the person who oversees and administrates the Mafia game. They are usually the person who designed the setup of the game they are running. Any action submissions, questions, or complaints should be directed to the moderator first, so as to maintain the integrity of the game.
The moderator is understood to be impartial in administering the game in that they don't try to sway the game to their liking.
For the curious, this is the page for mafiascum.net's Modding Requirements. Viewers who are not members of mafiascum.net are not bound by these, of course.