Iteration prompted by feedback is fundamental to creative design. Designers often use online communities to gather feedback, but there is little knowledge of how designers use these communities to iterate on their work. We studied iterative design practice in three active forums that target novice design critique in a popular online community. We collected a large corpus of projects (n=3,730) and comments (n=29,412). The data was analyzed to determine how often designers iterate on their projects, and which characteristics of the feedback correlate with iteration. Two surveys (n=38) were conducted to further learn how often and at which design stages designers post their work to the community. Our results showed that more and longer comments, comments with less positive tone and comments with more thought-provoking statements correlated with iteration. Our analysis also showed that two or more iterations were shared for only 21% of the projects. The survey results explained that the rate of iteration was due in part to designers sharing their projects with the community near the end of their design process. Our findings also suggest how online communities can better support iterative design practice.