Shifts in trajectories in thought communities and “wobbly” identities enacted in computer-mediated classroom discussions

•Past backgrounds and projections into one’s future influence the present.•The course as a community influenced students’ imagined future communities.•Students’ identities fluctuate with topics and others’ responses in online discussion.•A class community can support students’ membership goals for future communities.•Adding online discussion to face-to-face discussion has value for students’ learning.