Davis et al. (Davis, F. D., R. P. Bagozzi, P. R. Warshaw. 1989. User acceptance of computer technology: A comparison of two theoretical models. Management Sci. 35(8) 982--1003.) proposed, tested, and revised the Technology Acceptance Model (TAM), which attempts to explain and predict why users sometimes accept and sometimes reject information systems (IS). The research reported here (1) provides a confirmatory, empirical test of the revised TAM and (2) introduces and objective measure of technology acceptance, actual usage rather than self-report usage. Subjects' beliefs about the usefulness and ease of use of an electronic mail system, their intentions to use the system, and their usage of it 15 weeks later were measured in a longitudinal study. The results confirmed that the TAM is a valuable tool for predicting intentions to use an IS. The findings here combined with results from other studies in this area suggest that the original TAM may be more appropriate than the two-version revised TAM. However, the addition of an experience component to the original TAM may be a significant enhancement. In addition, the results support that self-report usage may not be an appropriate surrogate measure for actual usage.IS usage, technology acceptance model, IS implementation, perceived usefulness, ease of use