This study expands the traditional TAM by considering direct and mediating effects of users’ psychological factors on the adoption of e-service innovations. Specifically, this study proposes the influential paths from innovation design characteristics to innovation adoption through user perceptions in order to better understand how to design an acceptable innovation and identify the targeted consumer segments. This study developed experiments to test the results of various designs for a simulated new e-learning website. The results of the investigation indicate significant direct and mediating effects of user psychological factors on the innovation adoption. In other words, for predicting e-service adoption, the expanded model is more effective than the traditional TAM. The conclusions support the expanded framework with two pathways—one innovation characteristic-based and the other user perception-based—connecting to the acceptance of new technologies. The results also help partially explain the divergent and even conflicting effects of innovation characteristics of past research in TAM.