Everyone's the DM!

[Deremir]

Lately I've had an idea for a campaign where instead of the DM making all of the world the players interact with, the DM instead describes the world in broad strokes and the players fill in the finer details. I imagine it going something like this:

DM: you come to a fork in the rode, posted in the middle is a sign shaped like two arrows, with the right arrow having a depiction of a forest and the left arrow having a depiction of a cave. Beneath each image is some writing you can't quite make out from where you stand.
Player 1: I walk up to the sign and read the writing, next to the forest image it says "To the Forest of Enwonderment" and next to the cave image it says "to the Lair of the Pig Bat King"

Then when the players went to the cave the encounter that I had originally set up as simply a fight with a dragon has changed so that the dragon is also extorting a village of pigs with bat wings. I was hoping I could get advise from the playground on what the best way to go about this kind of game would be, and if there is any system that lends itself to this kind of game.

[The Glyphstone]

Something run in FATE might work, since it already has precedent in the use of Fate Points by players to make declarative narrative statements.

If you just want a non-mechanical thing, then any system will do, because what you're asking is for cooperative world-building, which is system agnostic. What you need is players you can trust not to abuse the narrative power you are sharing with them, and that is something you cannot legislate with rules.

[goto124]

DM: you come to a fork in the rode

I pick up the fork!

[Knaight]

There are systems which divvy up the GM role, or don't even have an analog - Microscope and Fiasco are the go-to examples here, but neither is sufficiently traditional for what you're looking for. In theory, any traditional system that gears itself more towards the story-telling side than the challenge-solving side should work for this, so pick your favorite and use this style of GMing.

[Âmesang]

In a somewhat similar situation my last group played with rotating referees… which would have been fine if we each ran unrelated adventures.

Instead we each ran a separate chapter of the Shackled City Adventure Path. There was a lot of background information left out between chapters (or just left out entirely).

[neonchameleon]

Lately I've had an idea for a campaign where instead of the DM making all of the world the players interact with, the DM instead describes the world in broad strokes and the players fill in the finer details. I imagine it going something like this:

Generally what works better is for the PCs to have an equal share in the broad strokes and the DM to take the lead on the finer details. And you're looking for Apocalpyse World (2E on Kickstarter right now) or Fate Core.

The reason it's the group setting the broad setup and the GM the detail rather than the other way round is that it generally makes for a poor game when the same people set up the problems as solve them. And when it comes to problems, the devil is in the details.

[ImNotTrevor]

If you want to do what amounts to D&D like that, use Dungeon World. It's Apocalypse World but with D&D classes and such. Probably a better fit for the desired feel than AW would be.

[Templarkommando]

First, I think to a certain degree this is already sort of assumed by a lot of DMs. A Player is already a DM in the sense that they have control over much of their backstory. In addition, I've played with several DMs that adopt a "Yes, and..." approach to DMing. If a player is worried that they might be the target of a conspiracy, surprise, they're the target of a conspiracy. There is a level to which this gets annoying though. For example, every time that the rogue checks for traps there is actually a trap gets really annoying. Probably the farthest that I can recall this being taken successfully was when I was in a one shot session where the party was investigating why the church was going to exorcise a particular child. The PCs attended a hearing to accept the child for exorcism and noticed that the case relied on "secret evidence," (which was shorthand for "The DM doesn't care enough to go through the motions of a whole trial.") The party immediately sensed some kind of conspiracy and started trying to bring down the corrupt members of the Inquisition. The DM hadn't thought of this at all beforehand, but decided mid-game that it made a good story and so he rolled with it.