Open source software is produced cooperatively by groups of people who work together via the Internet. The software produced usually becomes the “common property” of the group and is freely distributed to anyone in the world who wants to use it. Although it may seem unlikely, open source collaborations, or “commons,” have grown phenomenally to become economically and socially important. But what makes open source commons succeed at producing something useful, or alternatively, what makes them become abandoned before achieving success? This paper reviews the theoretical foundations for understanding open source commons and briefly describes our statistical analysis of over one-hundred-thousand open source projects. We have found, that leadership, clear vision and software utility may be causes of success early in a project's lifetime, and that building a community of software developers and users around an increasingly useful software product appears to be key to success for most projects later in their lifetimes.