Prior information systems (IS) research has established that individual perceptions of technologies determine their usage behavior, which is a prerequisite for the realization of business value of IT innovations. Hence, it is of critical importance to understand what factors shape individual perceptions of technologies. Perceived ease of use (PEOU) and perceived usefulness (PU) derived from TAM (technology acceptance model) have been consistently demonstrated to be two crucial factors impacting individual adoption and use of IT innovations. Moreover, the antecedents of PEOU and PU have received considerable research attention. Among the various antecedents, personal factors especially personality traits play a significant role but yet they have received limited attention. Considering that optimum stimulation level (OSL) as a general personality trait is closely related to the exploration and innovativeness in the adoption of IT innovations, this study builds on OSL theory and explores the impact of OSL on individuals’ PEOU and PU in the context of multi-homing use of social networking site (SNS) services. It was found that OSL has a significant impact on both PEOU and PU, whereby the impact is mediated by personal innovativeness in information technology (PIIT) and computer self-efficacy (CSE). Theoretical and practical implications that follow from the results as well as future directions are discussed.