This study proposes a set of hypotheses based on the perspective of the elaboration likelihood model (ELM) of persuasion, a conceptual model that explains the formation of member’s relationship quality and subsequent behavioral loyalty that are prompted by central and peripheral cues, namely argument quality and source credibility. Moreover, we also argue that the extents to which argument quality and source credibility influence the formation of relationship quality are moderated by two factors: member’s perceived personal relevance and user expertise. Based on a sample of 320 members from several well-known interest-based online communities, our research findings show that (1) both argument quality and source credibility have positive effects on member’s perceived relationship quality and relationship quality has a positive and significant effect on behavioral loyalty; and (2) both personal relevance and user expertise positively moderate the relationship between argument quality and relationship quality, and negatively moderate the relationship between source credibility and relationship quality. Implications for practitioners and researchers and suggestions for future research are also addressed in this study.