This study defines and explores relations between knowledge-seeking and social relationship networks, using data from a popular Q&A social network site. Our theoretical framework draws on Motivation, Common-goods, and Social capital theories to generate an understanding of the interrelationship of the two types of networks. A dataset consisting of 19 months of activity on Q&A Yahoo! Answers provides the basis for answering the following questions: Does a reciprocal relationship exist between the two networks? Is there a positive correlation in either size or growth between the two? Who are their members and actual participants? How does the social capital created by the social activities influence the asker's satisfaction? Finally, can the growth of one network come at the expense of the other? Findings suggest a positive correlation between the knowledge-seeking network and the social network; Social capital does contribute to askers' satisfaction and furthermore, under certain conditions, one network might grow at the expense of the other. Theoretical and practical implications for the mutual dependency of social ties and informational provision are discussed.