The purposes of the current study were (1) to examine the relationship between social networking service (SNS) dependency and local community engagement among Seoul residents, (2) to test the hypothesis that integrated connectedness to a community storytelling network (ICSN) is positively related to local community engagement, and (3) to investigate the moderating role of ICSN between SNS dependency and local community engagement. The current study is theoretically guided by communication infrastructure theory (CIT). We used online survey data collected during summer 2013 from a sample of 890 SNS users between the ages of 19 and 59 who lived in 25 districts in Seoul. We focused on four variables as local community engagement outcomes: neighborhood belonging, two collective efficacy variables (informal social control and social cohesion), and community activity participation. We found that SNS dependency and ICSN were positively associated with all local community engagement variables. We also identified the moderating role of ICSN between SNS dependency and the two collective efficacy variables. In addition, we found that closed SNSs (e.g., KakaoTalk) are more likely to facilitate community engagement than open SNSs (e.g., Facebook or Twitter).