The engagement of an online user community has been reported to be critical in the success of open design projects. However, most studies don’t consider the financial organizational contexts of their samples. Grounded in comparative case studies of the two biggest 3D printer communities — one supported by volunteers, another by a commercial firm, the paper contributes to the open design and open hardware literature with a typology of user community actions. We measured the types and intensity of different user community activities over time for the two cases. Results confirm that user community activities behave differently in profit-seeking or non-profit-seeking organizational contexts. We grounded potential causes through management team interviews as well as existing research theories. We conclude that the for-profit organizational context is associated with a difference in the design maturation process and the evolution of organizational openness.