How does a discourse community establish common ground for its members?

ENGLISH COMP

A discourse community is a special group who share subject matter, background, experience, values, and a common language (maybe specialized vocabulary, technical jargon, slang, or mutually agreed upon acronyms). You probably belong to many groups that fit this description and you communicate differently inside each one.

To what specific discourse communities do you belong? How does a discourse community establish common ground for its members? Use specific examples from your own experiences. How do you adapt the way you communicate for the different discourse communities in which you belong? How do you change the way you communicate for the different audiences you encounter outside your discourse communities?