Five full-time online mathematics instructors participated in a study to test the impact of using discussion forums as a space for formative assessments. Mean student posting activity and student quiz scores for sections in which the instructors used formative assessments were compared with previous sections in which formative assessments were not used. The research indicates that online discussion forums can be an important part of the learning process. Specifically, a certain type of formative assessment, known as classroom assessment techniques (Cross and Angelo 1988), may actually elicit more discussion forum conversation from students and positively impact student quiz scores.