Media richness was known as important in designing information and communication technologies (ICTs). However, no studies have examined how the four aspects of media richness could help fuel users’ commitment to virtual communities, indicating a gap. Hence, we use media richness theory and initiate to use its key elements (i.e., message certainty and message unequivocality) to construct a research framework. We collected 1,971 responses from virtual communities in online games and used structural equation modeling for testing the hypotheses. We found that immediate feedback and personal focus are positively related to message certainty and message unequivocality that are further positively related to network convergence and interdependence, thus contributing to commitment to virtual communities. This study is the first formally incorporating and testing the key elements of media richness, i.e., message certainty and message unequivocality, and examining how media richness of information systems could fuel users’ commitment to virtual communities.