This study focuses on two aspects of research findings from empirical studies on usability of user interfaces on the World Wide Web (WWW): (1) it examines the differences among users from novices to experts and their interactions with various user interfaces on the World Wide Web and (2) it compares task performance, confidence, and satisfaction among different types of user interface designs on the Web-based systems. Can we design user interfaces that are equally effective for all the subjects who have different levels of computer expertise? Implications of these results for various interfaces are discussed as well.