This paper explores how two organizations have changed their software development practices by implementing Open Source technology. Our aim is to understand the institutional changes needed in and emerging from this process. The paper develops a conceptualization building on the insights of entrepreneurial institutionalism and concentrating on the changing relationships of organizational groups in the areas of reward and communication. We identify the links between the 1) emerging yet embedded technology and 2) the underlying institutional reward and communication structures. In terms of contribution, we propose to move the Open Source 2.0 research agenda forward by concentrating empirical work on the