Enterprise crowdfunding offers a series of opportunities for voluntary or unplanned collaborations within organizations. In an enterprise crowdfunding experiment, we study the influence of interpersonal attributes-in-common on collaborations. Using ideas from Homophily Theory and Social Identity Theory, we analyze attributes-in-common in terms of multiple identity facets: of geography, of formal corporate structure, and of working groups/teams. We combine quantitative and self-report data to show how each identity facet has an influence on the likelihood of voluntary collaborations, and we show their "superadditive" combination. We propose new questions for theory, and we consider how our results can lead to new features and technologies to enhance voluntary collaborations in organizations. Copyright © 2014 ACM.