This work will focus on how different social relationships, namely shared identity and personal tie, will impact cooperative behavior, a form of social capital. I designed and conducted an economic game study to show that shared identity and personal ties work differently on cooperation among people and resource flow in social groups. Many factors can have impacts on social capital. Social relations are considered a major source of social capital. However, social relationships of different kinds have different underpinning mechanisms that govern behaviors, so I am wondering if these differences can lead to different consequences. Social network analysis and social tie research has been around for a while and got much attentions; social identity/shared identity research also has a long root in sociology and social-psychology. In my dissertation study, I want to see if and how these two make difference. I hypothesize that (H1) group members will put more resource in group-favoring activity and they will have less unsuccessful exchanges/transactions; (H2) in a social group, cooperation between people having ties will be higher than that between strangers and (H3) In groups with social identity, transactions between connected persons and that between strangers will be closer than in groups without or with low social identity. To test these hypotheses and other related issues, I designed an online economic game to help me explore the phenomena. My hypotheses are supported by varied degrees, and it informs research of community design and community informatics. Another value of this study brings to the community is the way I approach the problem, which is widely used in sociology and economics but very few in CSCW and HCI. One similar approach is the Shape Factory study. I designed an economic game to simulate a situation where both collective goal and individual goal presented at the same time and I also created a situation where players are not only put in dilemma of allocating resources, but also in dilemma of choosing partners. I believe this approach, and this design in particular, can contribute to the research in our community. The results of this study can be informative to studies in community informatics and computer-supported collaborative work. And it also contributes to wider social sciences by raising questions about social relationships and cooperation and showing initial effort in studying related issues. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]