In terms of company management for market segmentation and creating new market opportunity, Blog service has much important meanings. This study was designed to investigate the casual relationship among service quality, service value, customer satisfaction, and customer loyalty in the given blog service site "Cyworld". Through the empirical results, specific factors of blog service quality were discovered to be amusement, interaction, customization, reliability and convenience. Also rte confirmed that service value intervening between blog service quality and customer satisfaction plays an important role. This paper presents much implications both theoretical and practical side.