Critique is an indispensible part of creative work and many online communities have formed for this shared purpose. As design choices within the communities can impact the effectiveness of the critiques produced, it is important to study these communities and offer guidance for decisions. In this paper, we report the results of a case study exploring one large online community dedicated to critique in the domain of digital photography. We analyzed a large corpus of interaction data to understand the benefit of participation, the response dynamics, factors predicting critique ratings, and patterns of reciprocal interaction. Interviews with users were also conducted to uncover motives for participation and expectations of the critiques within the community. The results and insights gained from this work were distilled into recommendations for improving the design of systems that support community-based critique of creative artifacts.