Micro-blogging is a new social networking service (SNS) that can be viewed as an easily accessible, simplified blog. The simple and swift spread properties of micro-blogging make it different to the conventional SNS. However, little empirical results were provided in prior literature to elaborate individual’s behavior of micro-blogging use. Consequently, this study aims to explore the possible influence of individuals’ motivations on their self-disclosure and instant information sharing behavior as well as the extent of perceived social support in micro-blogging. Individuals who had experiences on Plurk usage were invited as subjects. The partial least squares (PLS) was utilized to examine the proposed model and hypotheses. Analytical results indicate that popularity and interpersonal needs significantly influence individual’s self-disclosure, while interpersonal and entertainment needs significantly influence individual’s instant information sharing behavior. Moreover, both individual’s self-disclosure and instant information sharing behavior have a positive relationship with the perceived extent of social support.