Introduction to the Mafia Game
Mafia was originally a party game, typically attributed to Dmitry Davidoff and cited as being created in 1986. The game models a conflict between a small group of informed players (the Mafia) and a large group of uninformed players (the Town) and was designed to analyze the psychology of players when placed in either group, especially as a study of the mob mentality. It made the jump to forums much later in mid-2000. The electronic medium allowed the game to evolve somewhat, featuring more complex setups and a slower pace that allows players to really consider their options, though it obviously lacks the necessity of a poker face found in the original form.
Some sites which can help you in knowing more about Mafia Games:-
Global Mafia Game Rules
Game Phases in a Mafia Game
The Vote Tally, Lynch System and Lynch Tie
What is Alignment?
The Factions in a Mafia Game
Role Abilities in a Mafia Game
Mafia Game Role Types and Night Action Resolution
Types of Mafia Game
Credits of the guide go to @Rohan, @Toujo and Rotaretilbo.