This Note reports on a field experiment that created two task forces, each composed equally of recent retirees and employees still at work but eligible to retire. They were given the identical tasks of preparing reports for their company on retirement planning issues, but they were randomly assigned to different technology environments. One group had full conventional office support; the other had, in addition, networked microcomputers with electronic mail and routine office software. Structured interviews were conducted four times during the year-long project; in addition, electronic mail activity was logged for the online group. Although both groups produced effective reports, the two differed significantly in the kind of work they produced, the group structures that emerged, and evaluations of their own performance. Although the standard group was largely dominated by the employees through the extensive use of informal meetings, the electronic technology used by the other task force allowed the retirees to exercise primary control. The authors conclude that use of computer support for cooperative work results in both quantitative and qualitative changes, but that effective participation in such electronically supported groups requires significant investments of members' time and energy to master the technology and a relatively high level of assistance during the learning process.