Several studies examining computer-mediated communications (CMC) in online courses have found low levels of participation under both voluntary (ungraded) and mandatory (graded) conditions. This is troubling since student participation is widely considered to have a positive impact on performance. Program-level data were analyzed to explore the relationship between three factors--(1) experience with previous online courses, (2) the course itself, and (3) the instructor--and subsequent participation. All three factors separately impacted participation levels in this voluntary CMC setting. Based on the findings, the authors recommend that researchers using CMC participation level as a study variable consider controlling for three global factors: previous online course experience, course, and instructor. Finally, the relationship between participation level and subsequent performance is tested, and the potential benefits of conducting future CMC research in voluntary discussion settings and with program-level data are discussed. (Contains 4 tables.)