This study examined the effectiveness of online social networking sites in developing the efficacy of student teachers during a practicum. The author found that such device was not as effective in enhancing teacher efficacy as many studies had hypothesized. Previous studies hypothesized that the popularity and familiarity of Facebook among student teachers would encourage them to use it as a platform where they can receive support, encouragement, and solutions when making decisions during a practicum. However, the findings of this study revealed that the efficacy of the participants in the Facebook community was only improved in area of Instructional Strategies, whereas that of the participants who were not part of this community improved in the areas of both Student Engagement and Classroom Management. The author concludes that an effective platform should involve both experienced teachers and other useful, easily accessible resources for student teachers. Furthermore, computer-mediated communication may not always be the optimal choice even with its commonality and familiarity.