Team messaging services represent a type of cloud computing applications that support not only the messaging among users but also the collaboration in a team. Accordingly, team messaging services have great potential to facilitate students' collaboration. However, only few studies utilized such services to support students' collaboration and further investigated the factors that influence students' acceptance of these services. To remedy this deficiency, this research not only employed a team messaging service to support the subjects' collaboration but also conducted a survey with a questionnaire designed for identifying the factors that influenced their intention to use the service. The research findings demonstrated that (1) social presence not only played an important role in influencing the subjects' intention to use the service, but also significantly affected their motivation in using it; (2) the subjects' intrinsic motivation played a more significant role than their extrinsic motivation did in influencing their attitude toward using and behavioral intention; (3) the subjects' attitude toward using the service exerted no influence on their intention to use it. These findings suggested that, when students collaborate through a team messaging service, their awareness of others' presence will significantly influence their motivation and intention to use the service.