I'm working with a professor from the College of Human Ecology on a new online course. She has an extremely content rich course. Our Instructor's Toolkit is proving to be useful and extensive, which is encouraging.
In a recent design meeting, she mentioned that she wasn't planning on using a discussion board. My suggestion was to create one or two forums in which the students could create a dialog around select topics. Participation should not be optional -- students should be prompted to work through a question, problem, or topic with some general guidelines. I tried to reinforce this suggestion by emphasizing the need to provide socialization opportunities for students in the course space.
This post and the accompanying comments come at the issue from a humanistic perspective. Which, I guess, is essentially how I've always considered use of discussion forums in online courses.