This study investigates the effect of the presentation of social network diagrams on virtual team members' interaction behavior via e-mail. E-mail transaction data from 22 software developers in a Korean IT company was analyzed and depicted as diagrams by social network analysis (SNA), and presented to the members as an intervention. Results showed that the SNA diagrams presented were effective in increasing the quantity of e-mail transactions among the members and in forming a community of practice. The findings suggest that SNA diagrams can be used as a cost-effective intervention strategy for virtual team members to actively share knowledge and collaborate as members of a network of practice.