This case study of an online graduate course determines the message characteristics of the instructor, volunteer teaching assistants, and students in online discussions, and proposes a mentoring, coaching, and facilitating model for online discussions. The researchers developed a coding system based on the literature of mentoring, coaching, and facilitating to identify the characteristics of conference discussion messages. The instructor fostered the development of volunteer teaching assistants into coaches and of student discussion facilitators into facilitators of learning. The proposed constructivist model fosters active learning, provides scaffolding for students to become facilitators of learning, and suggests creative ways for online instructors to manage different types of teaching responsibilities. Recommendations for further research are included.