The combination of online shopping and social media has contributed to the increase of social shopping activities. Technological advancements allow people with similar interests and experience to share, comment, and discuss about shopping from anywhere and at any time, leading to the emergence of online shopping communities (OSCs). This study reports on lab experiments and focus groups with 24 participants who actively engage in OSCs. We identify how informational support and social support affect user participation and relationships, the impact of social structure on interpersonal relationship formation between community members, and the development of desire to be socially connected with others through real-time conversations. Based on the findings, we discuss a series of design recommendations to facilitate users' emotional exchange and contribution behavior in OSCs, such as enhanced conversational interaction, and collaborative mini-tasks in a social shopping context.