As Knowledge Management (KM) has taken an essential position of managing businesses in the knowledge-oriented society, many companies have adopted Knowledge Management System (KMS) into their organization. Many have questioned, however, in the result and the effectiveness in KMS. The purpose of this study is to explore ways to improve the current KMS by analyzing and identifying the causes that affect effectiveness of KMS. Blog which is an effective tool for communication could be used for KMS in order to make KMS more user friendly and more effective. This research is intended to conduct an empirical study on the differences between Blog-based KMS and Non-Blog-based KMS and suggest resolutions to potential issues of KMS. Blog-based KMS users show higher degree of satisfaction and usage toward their system. The result of this study suggests that the differences between two groups are primarily on system quality and knowledge quality, and many of these differences come from functions and characteristics of Blog.