In 2009, Al Akhawayn University, a liberal arts college in Morocco, started a Writing Across the Curriculum (WAC) program. The question that drove my action research project was how to make writing more continuous in a WAC class. In addition to the writing assignments, weekly prompts on the discussion forum of the Learning Management System were used in a Differential Equations class. The discussion forum was chosen for several reasons. First, it helps students to have a clear audience: who are they writing for? In this case, they were writing for their classmates. Secondly, the goal was also to encourage students to interact with each other. Students were invited to answer each other's questions or to comment on previous posts. When analysing the posts on the forum, it was found that students' participation in the forum (the number of posts) was strongly correlated to their course grade. Students indicated that they had learned both math and writing skills. However, interaction between the students was limited.