This article describes the implementation of technology-mediated tasks in an English for academic purposes (EAP) curriculum at a Japanese university. The course addressed the needs of English majors at the school by enabling more efficient completion of academic work, including essay writing. One way that technology supported this goal was through tasks conducted via a chat module integrated into the Moodle course management system (http://moodle.org/). A classroom-based study was designed to evaluate the potential of convergent and divergent tasks to promote the development of second language competence through computer-mediated communication (CMC). During class, dyads completed two tasks via chat. Building on past research in face-to-face settings, quantitative and qualitative analyses of the discourse were conducted. Results are discussed in terms of the similarities and differences between these findings in CMC situations and those of the aforementioned research carried out in face-to-face settings. Implications for second language pedagogy, as well as methodological limitations, are discussed in the conclusion. (Contains 4 figures and 2 tables.)