Blogs, where people who have already formed close relationships offline maintain social ties by sharing personal information online, enjoy considerable popularity in Korea. However, such sharing of personal information carries a dual meaning: it serves as both a motivating factor for retaining members on blogs and a risk factor that may cause members to leave. This study empirically analyzed what types of personal information are exchanged on blogs and whether such exchanges of personal information have a negative effect of increasing privacy concerns on blogs. Additionally, the study examined the effects of two moderating variables that moderate the impact of personal information leakage risk on privacy concerns. The findings indicate that personal information carries the dual meaning of being both an attraction and a risk on blogs, and that there were some differences in the types of sensitive personal information between blog hosts and visitors. In conclusion, the negative effects and concerns can be reduced only when blog members are given control over the disclosure of their personal information.