Virtual community has gained much attention from academia and practice due to its great outcomes and potentials. One of the major issues here is how the virtual communities made such enormous outcomes with little control and reward, as wikipedia or Linux did. This study assumes that the voluntary participant’s performance has a direct impact on the productivity of the virtual community, and tries to find factors affecting the participant’s performance in the virtual community. We employ as theoretical bases Expectancy Theory, Goal Setting Theory, and literatures related with volunteers’ motivation. This study conducts the email survey from participants of knowledge service community of NHN, a leading Korean online company. We find that high-performing participants have individual ability, goal congruence, and the greater level of effort motivated by personal or collective functions.