This study explored what factors influenced learner participation in two sections of a graduate online course at a Midwestern university. Findings indicated that online learner participation and patterns of participation are influenced by the following factors: technology and interface characteristics, content area experience, student roles and instructional tasks, and information overload. Effective online learning requires interdependence for a shared understanding of learning goals in a learning community. Monitoring student participation and patterns of participation closely can help instructors identify student needs and scaffold learning accordingly. (Contains 3 tables and 1 figure.)