Social media technologies that enable interactive feedback during idea generation can complement existing modes of knowledge exchange in innovation management. Especially large, multinational companies use internal online idea competitions to promote intraorganizational knowledge exchange. Although current studies mainly focus on idea generation through crowdsourcing, little attention has been paid to the effect of online interaction between contributors on idea quality. Building on the organizational knowledge networks theory, this study examines online feedback activities, their contribution to knowledge exchange, and hence, how they increase idea quality. The authors identify three feedback characteristics of online idea generation presumed to affect idea quality: (1) the diversity of commentators (feedback diversity), (2) the extent to which feedback is elaborate and constructive (feedback constructiveness), and (3) the degree of facilitator interaction during idea discussion (feedback integration). This study also investigates how the idea authors' own feedback behavior moderates the relationships between feedback characteristics and idea quality. The results show that all three feedback characteristics relate independently and positively to idea quality. Author feedback shows a positive interaction effect with feedback diversity and a negative interaction effect with feedback constructiveness. The findings suggest that online feedback in idea competitions constitutes an important knowledge exchange process for idea generation. Companies that want to profit from firm-internal idea competitions should actively support online collaboration-e.g., through facilitators. Practitioner PointsThis study empirically investigated how feedback characteristics affect idea quality in firm-internal online idea competitions.Online idea competitions need to be arranged as an iterative feedback process between idea authors and commentators to increase idea quality.Heterogeneity in commentators' skills and competencies and the constructiveness of feedback are related to higher idea quality.Facilitator comments are important for idea quality, because they interconnect ideas and competencies within the firm and avoid homogeneous knowledge creation.