This study proposes a structural approach to examining online bridging and bonding social capital in a large virtual world. It tests the effects of individual players’ network brokerage and closure on their task performance and trust of other players. Bridging social capital is operationalized as brokerage, the extent to which one is tied to disconnected others, and bonding social capital as closure, the extent to which one is embedded in a densely connected group. Social networks were constructed from behavioral server logs of EverQuest II, a Massively Multiplayer Online Game. Results provided strong support for the structural model, demonstrating that players’ network brokerage positively predicted their task performance in the game and players embedded in closed networks were more likely to trust each other.