Contemporary first-year mathematics courses often provide students with online opportunities to interact with the course content, instructors, and each other. Asynchronous forums have become common, enabling students to raise questions and discuss the course material. What interactions emerge in such forums, and who are the students that take the leading roles in them? Do student participation patterns correlate with their course achievements, or do these forums provide an alternative space for engagement for those students who need it the most? In this chapter, I explore these questions in the case of 25 high-school students who took a special introductory university-level course in Linear Algebra. The course was taught in-person, accompanied by an asynchronous online forum opened to support students’ learning. The forum generated a considerable number of mathematical post-exchanges, the vast majority of which came from a small group of six students. The data analysis of the posts revealed a positive correlation between student thread-initiation and course achievements. Students’ activity in their self-initiated threads correlated with their activity in the threads initiated by their peers. In about half of the threads, the students sought verifications for their solutions to mathematical problems assigned for homework.