This page refers to the ideas of a Campaign and a Setting, as follows:
Gives an argument for the value of new Settings despite the continued value of old ones.
Argues that the choice of Setting should be determined by the purpose of a Campaign.
Defines the value of three new Settings defined on this site (Daydream, They Watch Over Us, Olori).
Here I refer to the idea of a Campaign. However, this is not necessarily intended to refer to a character's sum total of adventures; it is not a career. Rather, it is a beginning with an end: A character on a Campaign has a goal and started from somewhere; they're attempting to accomplish something. Thus, a Campaign may be a character's entire career, but isn't necessarily so: it could be a single arc therein.
Further, I reference a Setting, the purpose of which is defined below - but the scope of which can be set out here: A time at a place. Many Settings also encompass a degree of history, and even suggest potential futures: they describe not just a single time, but many. Further, there can also be many places in a setting - planes, continents, cities, or even such things as roads - and each of these can have their own history. A Setting can be very narrow or very sprawling.
Finally, I define a number of Mechanisms (themselves better, and more thoroughly, defined elsewhere), which are the manner by which we process a Campaign; that is, we play through a Campaign through a common framework of understanding the way the game is meant to be played. That common understanding is a Mechanism - and I believe it to deserve that capital letter because it's as fundamental to how we create stories through role-play as is a Setting.
I propose that a setting's purpose is to define a common ground, to provide certain ideas which the group can latch onto and run with. It is not meant to be a simulation; it is meant to inspire. A setting is specifically not a history book, or a CYOA, wherein all options are predefined - although a history is of value in providing concreteness to a theme, it is not the case that a setting is meant to restrict players; it instead acts through examples and a mythos.
By casually expecting a thorough understanding of a world's history, many game masters crush their players' willingness to freely work within the world.
To me, a setting is meant to enable players: to give actors novel concepts which can be worked with; to build from it something new yet familiar. Many ideas put forth by a setting are certainly of assistance to a game master - but the root of a setting is to find a new base for variance; to give a theme, a backdrop.
This variance is easily crushed with too much attention to detail. But it does imply that we can tell certain kinds of stories better in different settings...
It has been argued that vast swaths of all the successful Campaigns we've seen use one of a few different basic structures, or Mechanisms, as their core mode of operation (there are others, but they're mostly exceptional cases or archaic):
Dungeoncrawl. You're in a stone room. There are three exits. Which do you take?
Hexcrawl. You're on a forest trail. You have a compass. Where do you go?
Mystery. You're in a church. The priest was murdered. Where do you find out more?
(For details on each, see the linked series on Game Mechanics above.)
It turns out, in my opinion, that not all of these can be perfectly explored in every setting. Perhaps a character's path of self-discovery optimally involves a hexcrawl, but a well-mapped world leaves little to explore; perhaps a character wishes to make themselves available to help the world, but it's difficult to position oneself as an authority for subtle matters of intrigue when the world is quaking and the fires of Hell are spilling themselves forth from the cracks.
These are perfectly fine places and times to set some campaigns, but no single setting is perfect for all uses.
The settings defined on this site are very purpose-built. They are not necessarily throw-away, but they are intended only for a narrow range of purposes: Using them outside of that range is easily done, but must be with intent, for there will be some moderate amount of supplementary material one must design.
In particular, the three settings present at the time of writing neatly fall into each of the above categories of Campaign:
The Radiant Planet Olori. This is a world explicitly about validating the experience of what's been called "murderhobos." (See here for more details and a related discussion.)
Dungeoncrawl: It fits quite naturally into the Dungeoncrawl mechanism, somewhat obviously.
Hexcrawl: A hexcrawl run in Olori would be an unimaginably different experience; it's hard to meaningfully call such a thing a hexcrawl. This is not necessarily a good thing, but it is also not necessarily a bad one. (Related: consider certain concepts described in the GM Guide.)
Mystery: Although not immediately obvious, a Campaign set inside the walls of one of Olori's Cities makes for a convenient locale, with various novel reasons for machinations. Further, given the ease of creating a new City, each mystery can have a wholly new rationale.
Daydream. Unlike many invented settings, Daydream is not a setting about powerful nations - it's a setting about ideals. Here, this mostly takes the form of competing religions.
Dungeoncrawl. Daydream is a fairly typical setting at the scale of a city and its catacombs; although not the intent of the world, a dungeoncrawl is very straightforward to insert into most settings, and Daydream is no exception.
Hexcrawl. Daydream's world is poorly-defined, in the sense that its land is much less important than its ideas. The way one wrests control, here, is by talking, not by finding. Hexcrawls are by no means impossible to run here, given the lack of maps; however, adventurers who take this path may not be especially inspired by the setting.
Mystery. This is the intended purpose of the setting. There are various major players at work in the world, operating at many different levels; a mystery suits it quite well.
They Watch Over Us. Although perhaps the most typical setting seen thus far, with its focus on nations and politics, TWOU features a novel context: the Fae.
Dungeoncrawl. Although by no means impossible, using TWOU as the context for a dungeoncrawl is somewhat wasteful, since few of its traits will impact a typical 'crawl; using a more familiar setting is recommended.
Hexcrawl. Being the most traditional of the settings, TWOU is very well-suited to a hexcrawl: It has enough novelty to lead to interesting situations, but enough familiarity to keep things believable.
Mystery. With the presence of the Fae, the machinations of the nations, and the pressures of more individual actors like guilds, a mystery would work especially well, at most any scale.
In summary: It's easy to run a Campaign in any appropriate Setting, so long as the Mechanism which underlies it is chosen carefully. Likewise, many Mechanisms are reasonable, but many poor experiences with such things can be explained as not playing to the strengths of a Setting or a Campaign.
One might suggest that my usage of "setting" is somewhat obfuscatory; certainly a single setting can refer to a wide variety of places at a wide variety of times, and by this to say one "uses up" a setting is unfair. We might think of a plane and its many continents, each with their own many past years; one cannot expect to ever fully bore of a certain world. To this I say: Of course! That's quite fair. But such a range of ideas can also be hard to unravel for those not intimately familiar! A very narrow setting can serve an inspiring purpose, and a very broad one can become very comfortable. I argue that they each have a purpose.
On the proper scope of a Setting: