This study identified direct and indirect effects of Web users' age, gender, technical training, computer and Web competencies, perceived usefulness of the Web, and perceived needs of the Web on their Web use. A theoretical model for the variables that affect individual differences in Web use was conceptualized through related literature and research reviews in the areas of computers, online networking, and the World Wide Web. In this study, an ex post facto design was employed to investigate factors that were related to Web use. Results revealed that there was a negative total effect of the age of participants on the amount of time spent using the Web. Also, their perceived needs of Web use, technical training they had received, perceived usefulness of the Web, and their computer and Web competencies had positive direct effects on their Web use. In particular, young participants spent more time using the Web and showed slightly more positive perception on the usefulness of the Web than more mature participants did. The results also showed that there were gender differences in the participants' computer and Web competencies in which the male participants showed a higher level of competency in Web use. Overall, the findings of this study suggest that basic skills and knowledge of Web use should be provided formally or informally to learners in order to facilitate the Web use for participants of Web-based instruction. It is also recommended that communication channels be provided for participants of Web-based instruction in order to facilitate their Web use. (Contains 85 references.) (Author/AEF)