This study investigates how teachers develop and extend their understanding and knowledge of teaching and learning with digital technologies in a primarily online Master of Science program. The investigation focuses on exploring the relationship between developing an online community of learners and the construction of technological pedagogical and content knowledge (TPACK) during the online Master's program in mathematics education and science education. The purpose of this study was to explore rural elementary and middle school in-service teacher's perceptions of the relationship between their development of and participation in an online community of learners and the construction and extension of their TPACK. With a focus on engagement in an online community of learners, this study used a social-constructivist perspective transitioned to an online context as a framework for supporting the research. To shed light on the relationship in question, a general question was posed: How do teachers develop and extend their understanding and knowledge of teaching and learning with digital technologies (TPACK) in an online education experience? Three questions were used to guide this research: (1) What is the mediating effect of engaging in an online community of practice during the program on the participants' perspectives of teaching and learning with integrating digital technologies? (2) How do the instructional strategies used in the program mediate the development and support of an online community of learners? (3) What are the participants' perspectives of the development of their understanding of teaching and learning with digital technologies as a result of their participation in the online educational experience?

Through a case-study analysis of interviews, classroom observation narratives, and online course artifacts, this study identified two primary mediating effects resulting from engagement in an online community of learners. The first effect was in providing the participants with tools and support for developing personal relationships where they were able to feel part of a meaningful community of learners. This learning community proved to be an essential environment and structure in which the participants shared aspects of themselves in ways that helped others connect with them as people, more than text on a screen.

The second effect was to provide an avenue for extended sense making discourse resulting in participants' individually building their TPACK. The online community of learners provided an environment and structure in which the participants were able to share ideas and understandings of the content and concepts presented in the online courses. These academically focused interactions were a necessary component in facilitating individual TPACK building.

An essential underlying element in both these effects was the importance of instructor monitoring and mediating of participant engagement in facilitating the formation and continued development of the online community of learners. Having the instructor act as a “vision keeper” throughout the entire program, where they monitored participant engagement and mediated these interactions to maintain an appropriate focus, was an essential component in initiating and continuing both socially and academically focused engagement behaviors. The findings identify the critical nature of developing and engaging in an online community of learners, facilitated through continued support by instructors, in developing TPACK in an inline educational experience.