Marketers aim to increase active participation in their brand communities on social networking sites to achieve favorable brand outcomes. This paper is the first to analyze the moderating influence of community type (i.e., whether members primarily strive for social versus functional goals) on the effect of (a) negative word of mouth (nWOM) and (b) positive word of mouth (pWOM) on brand community outcomes. Specifically, we analyzed the effects on community members' perceived goal instrumentality of social network brand communities (i.e., whether the community increases the likelihood that personal goals will be achieved) and active participation in these brand communities. The results of a field study and three laboratory experiments reveal that nWOM evokes more negative consumer reactions in social-goal communities than in functional-goal communities. However, pWOM evokes more positive consumer reactions in social-goal communities than in functional-goal communities. Overall, the results have important managerial implications for effectively managing the occurrence of nWOM and pWOM in social network brand communities.