Sharing members with other online communities can be problematic for community responsiveness, as less member time and attention become available for the focal community. However, member time and attention spent externally have the potential to generate knowledge that bolsters the focal community’s responsiveness. Little is known about when member time and attention spent externally become such generative resources. Building on and extending the knowledge collaboration theory of online communities, we examine the network conditions that enable the generative effect of member time and attention spent externally on community responsiveness. We propose a contingent model wherein a focal community’s external bridging (the extent of bridging nonredundant communities) and internal bonding (the extent of cohesion among members) jointly moderate the effects of member time and attention spent externally on community responsiveness. We theorize that external bridging provides the opportunity to access novel external knowledge and that internal bonding improves the motivation to share knowledge to assist others. Our results show that member time and attention spent externally have a positive effect on community responsiveness only in the presence of both external bridging and internal bonding. The study has important implications for advancing the boundary conditions regarding generative resources and online knowledge collaboration.