The purpose of this study was to explore variables related to characteristics of high school students using computer-mediated communication (CMC) technology. Student characteristics are explored with respect to gender, academic self-concept, parental education, skill and experience with technology, communication apprehension, and social influence. The educational networking testbed of CoVis (Learning Through Collaborative Visualization) at Northwestern University (Evanston, Illinois) provided an ideal setting for exploring ways that students use CMC technologies. There are four particular CMC tools available to students in the CoVis project: electronic mail (e-mail), Usenet news, circuit-switched desktop videoconferencing, and a network-based collaborative, multimedia notebook. Subjects of this study were 280 students (from all 4 grade levels) from 2 suburban Chicago high schools. Surveys were administrated to students to gather data on student experience with computers and CMC tools, and student beliefs and attitudes towards both CMC tools and school. The factors that explain differences in CMC tool use fall into two basic categories: those that can be compensated for in the short term with proper intervention and design, and those that cannot be directly compensated for, but are still useful for understanding how different students might react to the introduction of CMC tools. The factors that fall into the first category are experience with computers, social influence with respect to CMC tools, and communication apprehension. Factors in the second category include students' academic self-concept, parental education, and gender. The combination of these factors explains why some students used CMC tools more than others. (Contains 62 references.) (AEF)