Something I have noticed while talking to people on the IRC channel is that they refer to Worlds and Settings and something completely different. In the eyes of the community, what exactly consists of a "setting" and what is a "World"?
I'd say that a "World" encompasses everything, but a "setting" is where the action takes place, like a town or a country. To use one of my favorite fantasy settings, Dragonlance, the world itself is the world of Krynn, but the Dragonlance setting proper is the continent of Ansolon. There are other continents, islands, countries, etc, but the main action for the books, movie and comics was Ansolon.
Of course, "World" could encompass more than one, per se, like in Star Trek. The world of Star Trek is our galaxy, but the setting is the planets of the Federation in the Alpha Quadrant.
I take a similar approach. A world is simply an area, a setting is a world as a story is produced, and encompasses much more than simple geographical or cultural elements. To use an example, in my Waypoints setting the corruption in the Argentine police force is a world element. The utter inability of a PC owned jeep to survive more than two sessions in a row without being annihilated is a setting element. Its a tiny thing, with no real connection to the world at large, but its a part of the setting that has spawned many memories.
The [-] die.
Hmmm, I have a completely 180 degree interpretation. I use "setting" to refer to the entire flavor of the genre that the game is taking place in, whether it takes place in a single village or across dozens of planets. The Setting is something like "Dragonlance" or "Honor Harrington" or "Paul's Space Marines Setting" - it is the flavor, genre, style, themes, culture, etc. of the adventure or campaign. I tend not to use the term "World" much at all. Terra Incognita is the Setting of a Campaign I am currently running. So far, the Player Characters have been to dozens of Locations (A Museum in Boston, A Warehouse, A Mansion, the Azores, the Vatican, Paris, London, Iceland, etc.) so I guess I use Locations for places instead of Setting as in one of the example above.
I'm with the latter group in this thread so far. We use the term setting in a similar fashion to "set up", e.g.: the setting is Victorian England, demons exist and the players work for a secret government department charged with seeking out and destroying other-world entities.
I don't think we use the term "world", less it be in the form of a titular, i.e. "The World of Glorantha".
It sounds like using World and Setting has it's place when talking about fantasy rpg, where the World is, well, the world of the RPG. But when you move it to something based on the modern world or move it to a future or sci-fi based rpg, World has no meaning and Setting encompasses both the "world", the genre and everything in-between.
World is still plenty useful in sci-fi, particularly hard sci-fi where there isn't going to be much, if any, interplanetary travel. Otherwise, it becomes a term that covers planets, moons, rings of a planet, large space stations, large asteroids, and in very, very unrealistic settings asteroid belts (the kind ships weave between, rather than changing course to see a single asteroid.)
The [-] die.