"Engaging" and "connecting" are often buzzwords associated with social media. While much has been made of its use and value for professional learning for teachers, classroom uses of social media with students have received less attention. The Global Read Aloud (GRA) is a collaborative book study where classes read a common book and then "connect" and "engage" with other classrooms from around the world online. In this study, the authors conducted a content analysis of Twitter uses of the Global Read Aloud to investigate how teachers engage around a shared reading experience and connect with other classrooms. The authors analyzed over 2,000 tweets across five book forums from the 2019 iteration of GRA. Results identify ten unique activities in which participants engage. Findings also suggest that the types, frequencies, and nature of these social media activities may not reflect the depth and complexity of engagement that is often touted by advocates. The authors share implications that can offer insights to educators considering similar types of online participation.