And, you must respond to other student postings. This is your way of demonstrating that you are participating in the course. My students at Saint Joseph College have used it with very positive effects. Some have compared it to passing notes in class. What a great way to engage students in a writing activity.
Social motivation is so strong.
I think that I would have loved threaded discussion as a literacy activity. It can also enrich other disciplines as well. Other students see it as a chance to practice writing and conversation with others, much as a journal and responses to journal entries do. It allows us to compare our different understandings and to teach each other. It s important that you write thoughtful comments and not just take a passive approach.