Purpose - This study investigated not only social network service (SNS) characteristics’ effects on continuous use intention and reliability, but also the effects of continuous use intention and reliability on purchase intention. Research design, data, and methodology - The subjects comprised 274 SNS users in their twenties. The research was conducted over three weeks from October 16, 2013 to November 6, 2013, using questionnaires. A total of 267 copies were collected; 255 copies were used after excluding unsuitable copies. Results - Marketers who used SNSs should establish a bi-directional community and SNS page information exchange. SNS marketers should exchange useful information quickly through SNS pages, to differentiate themselves from competitors. Enterprises should use SNSs for marketing, considering not only continuous use intention but also reliability, to elevate product purchase intention. Conclusions - The study had limitations. Most subjects were students aged 24 to 28 years; the findings cannot be generalized. Second, personal computers (PCs) and smartphones had similar influence. Third, the preferences and/or characteristics of each SNS type were not reflected in marketing.