Despite the positive potential of the online social networking platforms, the longitudinal studies regarding how children participate in digital storytelling communities is still scant in the literature. This study investigated how 26 elementary students participated in a 2-year digital storytelling community mediated by a social network application. By analyzing the students' weekly responses, social networks, and their language learning performance, the results suggested that their oral reading proficiency improved along with their participation in the long-term activity. It was also found that the community features impacted the students' sense of engagement in the activity. The feature of the learning community that allows students to team up with partners to complete a story improved their engagement and motivation. The social network analysis found that multiple literacies including multimedia processing, language, and collaboration were all considered by students as important criteria for the partnership to complete the collaborative digital storytelling work. However, such a prolonged collaborative digital storytelling activity also introduced new challenges for those students demonstrating unfavorable collaboration profiles as they needed to learn how to collaborate in order to team up with others. The implications of the findings for educational practice are discussed.