Despite their potential value, the mobile Internet services in the domestic market have not been widely accepted as industry experts have expected. To understand why, this study uses the TAM, Technology Acceptance Model, and explores the factors affecting the usage behavior of the end-users. Based on statistical analysis of survey data, we show that social influence and perceived ease of use affect perceived usefulness, and that self-efficacy and focus significantly influence perceived ease of use. Furthermore, perceived usefulness is shown to play a significant role in explaining actual usage of the mobile Internet services. However, contrary to the hypothesized relationships, service quality, focus, and innovativeness of users turn out to have little impact on the traditional endogenous TAM variables such as perceived usefulness, perceived ease of use, and actual usage behavior. Based on these results, we attempt to provide managerial implications for the domestic mobile Internet service providers and to suggest future research directions in this domain of research.