This study analyzes the relationship between class size and student online activity patterns in a series of 28 graduate level computer conferencing courses. Quantitative analyses of note production, average note size, note opening and note reading percentages found a significant positive correlation between class size and mean number of notes generated. Significant negative correlations were found between class size and average note size and between class size and percent of notes opened. Analyses of average reading speeds among large classes and small classes revealed that students in large classes were more likely to scan lengthy notes (i.e., notes that contain more than 350 words). Possible explanations for these results are discussed.