In this paper, we1 study new organizational forms for production processes that emerge in large scale Free/Libre Open Source Software (FLOSS) projects. We will focus on the textual artifacts known as “Programming Guidelines” and on the rules and practices they contain. Our reflection is grounded in the practical activities of the people involved in the innovation processes. In particular, we take into account how in FLOSS to become a peer (“Peering”) is an hybrid result of social dynamics and artifacts actions. We will show how Programming Guidelines participate in building boundaries around the potential participants and in defining the legitimate form of participation in terms of coding practices. Our conclusions emerge from the analysis of two empirical cases: the operating systems OpenSolaris and the geographical information system GRASS.