[DL] What is "Western"?

[Aaron Chusid <aaron@to-the-point.org>]

Silly question, I know, but as I get ready to GM my first ever DL campaign 
(not having even played before), I want to have a better feeling for what 
Western is.

It's more than just Cowboy hats and horses and six shooters and showdowns 
at high-noon; those are the decorations, not what really makes it a western.

What are the themes, the motifs, the elements, plot devices, character 
traits, and so on that I should keep in mind to make the world, the story, 
and the npc's *feel* western?