The usage of Instant Messenger (IM), as a synchronous communication medium, is growing in the workplace. However, little empirical work has been conducted to investigate the impact of Instant Messenger (IM) on work performance and job satisfaction. In this study, we attempt to understand the impact of IM in the context of a social network. Student subjects will be used as our sample since the behaviors of college students are very likely to be carried into workplace. In addition, most of these students have some part time jobs.