Quote from neonkitty
"Describe the social nature of writing, particularly the role of discourse communities at the local, national, and international level."
Da fuq does that even mean? o_O
A discourse community is a a group of communicators with a common goal or interest that adopts certain preferred ways of participating in public discussion; you'd usually need membership to these communities and follow their communication norms (businessmen would have their own community, lawyers, politicians, doctors, mechanics, computer programmers etc etc). If you don't follow these norms, you're in risk of being kicked-out or down-talked (commonly seen in politics).
I think it's just saying to describe how writing affects societies (academic papers, books, lectures, debates, TV and radio programming) and how people are viewed in society. For example, how you'd write this assignment vs a text or email. You wouldn't use shorthand or contractions because you're in academia now and as a scholar, you're educated enough to know the standard conventions of paper writing.
At least, that's what I understood. IDK how to connect to the international level. @____@ I did find this on Google though:
“I would say, in sum, that most people stand between two kinds of discourse communities: local discourse communities, groups of readers and writers who habitually work together in companies, colleges, departments, neighborhoods, government agencies, or other groups defined by specific demographic features; and global discourse communities, groups of writers and readers defined exclusively by a commitment to particular kinds of discourse practices and preferences, regardless of where and with whom they work” (121). (from "M. Jimmie Killingsworth’s “Discourse Communities–Local and Global.” (1992))
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http://i.imgur.com/LxhWm.jpg (will reformat this some day…)