The rapid adoption of Internet technology has accelerated the establishment of platforms for virtual interaction that overcome the inherent time and space limitations of face-to-face communication. The objective of this study is to investigate the individual and network level mechanisms that characterize interactions on these electronic knowledge networks (EKNs). Toward that goal, we develop a simulation model of a thread-based asynchronous EKN and provide results based on 330 runs of the model (simulating a total of 3,643,942 messages generated by 38,860 authors). This study contributes to our understanding of electronic knowledge networks by demonstrating the importance of structural characteristics in influencing participant behaviors. We focus specifically on the role of preferential attachment (the tendency to associate with the most popular participants) and mutuality (the tendency to maintain symmetry in relationships with others) in network formation. By using a simulation method and taking into account the nature of interpersonal ties, the study extends previous mathematical models of network formation to the specific setting of online knowledge exchange between individuals.