Instructors who teach in online learning environments have the unique opportunity to enhance the interaction of their students through an online threaded discussion board. With effective planning and skillful facilitation techniques, this venue for posting messages can be used as a resource to engage learners in becoming an interactive and cohesive learning community. This case study centered on participants enrolled in a web-based, graduate level professional development course for educators at a large midwestern university. Using the constant comparative method of analysis, the researchers analyzed threaded discussion board transcripts, interviews with the instructors, and formative and summative course evaluations to code for themes and categories from which emerged a model for stages of online group development. Initially "virtual" strangers, participants became an interactive and cohesive learning community by the end of the five-week course. Five stages of online group development are identified: (a) Introduction, (b) Identification, (c) Interaction, (d) Involvement, and (e) Inquiry. These stages provide implications for teaching and learning online.