“I can think of three major typologies of classroom discussion board, at least as far as the traditional definition of one i.e., students/instructors post topical posts and others respond to both posts and responses:The Waste Land, which I hinted at above. Tumbleweeds. Nobody for miles, except for perhaps a lonesome professor shouting, “Hellooo! Is there anybody out there?”The Organic Garden, also mentioned above. Discussions grow and flourish naturally, and volunteer posts sprout forth from the screen.The Industrial Farm, where regimented numbers of postings and responses appear in chartered rows and in exact numbers. Usually planted via a line in the syllabus that says, “Students will, on a weekly basis, make one discussion posting, respond to three other discussion postings, and respond to two responses.””
Always great discussion from the College of William and Mary Academic Technology Department –
via Gardens of Discussion: What Makes Online Communities Work? — Academic Technology.
New Images of Education 