According to Wikipedia, the term discourse community

was first used by sociolinguist Martin Nystrand in 1982, and further developed by American linguist John Swales. Writing about the acquisition of academic writing styles of those who are learning English as an additional language, Swales presents six defining characteristics:

A discourse community:
  1. has a broadly agreed set of common public goals.
  2. has mechanisms of intercommunication among its members.
  3. uses its participatory mechanisms primarily to provide information and feedback.
  4. utilizes and hence possesses one or more genres in the communicative furtherance of its aims.
  5. in addition to owning genres, it has acquired some specific lexis.
  6. has a threshold level of members with a suitable degree of relevant content and discoursal expertise.

James Porter defined the discourse community as: “a local and temporary constraining system, defined by a body of texts (or more generally, practices) that are unified by a common focus. A discourse community is a textual system with stated and unstated conventions, a vital history, mechanisms for wielding power, institutional hierarchies, vested interests, and so on.”

In effect, a discourse community is a group of people who not only share a particular form of communication but are also shaped as a group by that particular form of communication. The students in a class form a discourse community, as do the members of a group on facebook.

Consequently, discourse communities are everywhere. One such community that I’m a part of is my department, hereafter referred to as the “departmental community.” For many of us, our belonging to the departmental community is the primary structuring force in our relationship — I don’t see them or communicate with them outside of this community. But there are also smaller discourse communities within larger ones. There is, for example, a network of “younger” faculty within my department (subsequently referred to as the “new community,” one that includes many (most?) of the people hired within the past decade or so, that also forms a discourse community.