One of the components of online communities is that regardless of anonymity or size, we tend to gravitate into tribal groups based on what we perceive as like-minded individuals and in some cases “alphas” within a group.
Have we started to form into tribal groups based on the history of posts and discourse with certain people within the course? Within the course are those you tend to post first each week and set the tone or direction of discussion. And parts of the groups that sit on the “periphery” come into the discussion after a series of posts have established a direction for the discussion.
One of the questions I would ask in terms of community building and an individuals coming into the discussion from the periphery depend their reluctance to establish a thread, are intimidated by being first, the group or the technology?