Traditionally, the Dungeon Master assumes god-like powers in a game of D&D. They are the omniscient narrator with power over everything but character choices. They build and tell the story, they populate worlds, they interpret rules. They even have the power to set aside rules and rolls, at their discretion (this is a whole other thread). But lately I've been questioning how necessary this power dynamic is.
I recently ran a session of my 5e campaign using modified Fiasco rules, meaning that the game took place as a series of scenes, and each player, including me, was a co-equal narrator - one person either started or finished a scene, taking turns, and the rest did the opposite. I had some control in that I set up the original scenario and put locations, objects and NPCs into play before the game started, but during play the plot was wide open - it was a mystery and I didn't know who did or why any better than the other players. We worked it out together through the course of the game. It was fun!
I also encourage players to improvise plot details that they want for their character, trusting that they too have the best interest of the game at heart. Lately, I have told them that they can add not just suggestions but major plot points, only requesting that they give me time to prepare if the plot point will involve having to create a dungeon or something (a lot of things we can improvise on the fly).
I'm finding that the more control I give up, the more fun I am having at my games. And it is making me suspect that centralizing power in the DM is not as necessary as the rules presuppose. Depending on the group.