When do you need a GM?
Traditionally RPGs centralize many responsibilities and authorities in one player, the GM. That's not necessarily bad, but it isn't necessarily good, either, and it's certainly not mandatory. I am going to look at some traditional functions of the GM to see why we put them in one player's hands, and how we might distribute the responsibility for these functions differently. A GM traditionally does a whole bunch of different things: Pitches the game Organizes play sessions, including recruiting players Knows the rules and teaches others Leads creatively Creates the background ("worldbuilding") Creates the scenario for play Runs dramatic coordination Frames scenes Says "what's going on" generally Plays all side characters Resolves in-game tasks and conflicts Pitches the game, organizes play sessions, knows the rules. If the entire play-group is interested in gaming and excited about games, anybody should be able to do these things. (This or that ...