Buddies, serving as in-group influencers to aid demographically similar cobuddies, are extensively used in face-to-face support groups to enhance positive social influence. The authors examine the efficacy of buddies in online support groups and investigate underlying mediating processes using social network analysis. They observe what happens when members of support groups for quitting smoking, including members who are relatively active and less active in the group, after a few days are called on to be buddies and assigned to specific cobuddies. The findings indicate that, consistent with normative expectations for buddies, members form especially strong ties with their designated cobuddies. The more active buddies are in the group, the stronger the ties they form with their cobuddies and, in turn, their cobuddies form stronger ties with group members overall, which then relates to cobuddy goal attainment. The findings suggest that interactive marketers should consider using buddies in online support groups but observe activity levels before making buddy assignments, because positive outcomes are contingent on buddies being active in the group. Marketers should also ensure that online support group members post to everyone, not just their buddies, because ties formed among group members as a whole are crucial for goal attainment.

Keywords: health goal attainment; in-group influence; online support group; quitting smoking; social influence; social network analysis; tie strength.