Students' use of distributed Problem-Based Learning (dPBL) in university courses in social economy was studied. A sociocultural framework was used to analyze the actions of students focusing on their mastery of dPBL. The main data material consisted of messages written in an asynchronous conferencing system by 50 Swedish college students in 2 courses held in different years. Results suggest that when students engage in dPBL, they take responsibility for their learning by creating necessary artifacts. Students gradually establish mutual agreement among the group members using a highly conversational approach. Establishing function on a group level was crucial for mastery of dPBL. Commenting on each other's work allowed students to exchange feedback in a collegial manner. Commenting on each other's comments promoted community building in a way that fostered reciprocity as well as engagement. (Contains 39 references.) (Author/SLD)