Despite the growing popularity of Online Social Networks (OSNs), the workload characteristics of OSN servers, such as those hosting blog services, are not well understood. Understanding workload characteristics is important for optimizing and improving the performance of current systems and software based on observed trends. Thus, in this paper, we characterize the system workload of the largest blog hosting servers in South Korea, Tistory1 . In addition to understanding the system workload of the blog hosting server, we have developed synthesized workloads and obtained the following major findings: (i) the transfer size of non-multimedia files and blog articles can be modeled by a truncated Pareto distribution and a log-normal distribution respectively, and (ii) users' accesses to blog articles do not show temporal locality, but they are strongly biased toward those posted along with images or audio. Keywords-Online Social Networks (OSNs); Workload Characterization; Measurement; ...