This paper proposes that social categorization is driven by an ecological dynamic that operates in two planes: feature space and category space. It develops a theoretical model that links positions in feature space to label assignments in category space. The first part of the model predicts that movements in feature space affect label assignments in category space, with proximity to labeled clusters affecting label adoption. The second part predicts that the structure of category space affects this relationship. For lenient labels, positions in feature space are more weakly related to label adoption in category space. An empirical analysis of software producers, based on their positions in a feature space of patents, and a category space of market-label affiliations, supports these predictions. The results imply that social classification is characterized by this coupled ecological dynamic. Further, our findings have implications for the evolution of categories, suggesting that lenient categories will become more lenient, while constraining categories will become more constraining.