The importance of using systematic formative assessment to guide students toward meaningful learning has gained more recognition in the education community in recent years. This form of assessment is characterized by task-oriented feedback in a low-risk environment, which is believed to promote mastery goal orientation and self-regulated learning. In spite of these apparent benefits, formative assessment strategies are generally underutilized in the science disciplines. In this article, I describe an e-mail-based formative assessment program, which was established to encourage students to revisit first-year general chemistry material regularly in a low-risk and supportive environment. Because the aim was to foster a mastery goal orientation, no grades were assigned to students' responses, and participation in the program was optional. I describe the academic profile of students who participated regularly and their patterns of participation over the course of five years of implementation of this program. (Contains 2 tables and 4 figures.)