The open source development model has become a paradigm shift from traditional in-house closed-source software development model, with many successes. Traditionally, open source projects were characterized essentially by their individual volunteer developers. Such tradition has changed significantly with the participation of many organizations in particular. However, there exists a knowledge gap concerning how open source developer communities evolve. In this paper, we present some observations on open source developer communities. In particular, we analyze git repositories of 20 well-known open source projects, with over 3 million commit activities in total. The analysis has been carried out in three respects, productivity, diversity and growth using the Spearman's rank correlation coefficient, diversity index and the Gompertz logistic curves, respectively. We find out that (a) the Spearman's rank correlation coefficient between active contributors and commit activities reveals how changes in the size of the developer community impacts the productivity of the community; (b) the diversity index of an open source developer community reveals the structure of the community; and (c) the growth of open source developer communities can be described using different phases of growth curves as in many organic matters.
The success of the Linux operating system has demonstrated the viability of open-source software, an alternative form of software development that challenges traditional assumptions about software markets. Understanding why developers participate in open-source projects is crucial for assessing the impact of open-source software. Their motivations fall into two broad categories: internal factors (e.g., intrinsic motivation, altruism) and external rewards (e.g., expected future returns, personal needs). The results of a survey administered to open-source programmers are summarized. This paper develops an inductive theory of the open source software (OSS) innovation process by focussing on the creation of Freenet, a project aimed at developing a decentralized and anonymous peer-to-peer electronic file sharing network. We are particularly interested in the strategies and processes by which new people join the existing community of software developers, and how they initially contribute code. Analyzing data from multiple sources on the Freenet software development process, we generate the constructs of "joining script", "specialization", "contribution barriers", and "feature gifts", and propose relationships among these. Implications for theory and research are discussed.  Preface 1. Property and the Problem of Software 2. The Early History of Open Source 3. What Is Open Source and How Does It Work? 4. A Maturing Model of Production 5. Explaining Open Source: Microfoundations 6. Explaining Open Source: Macro-Organization 7. Business Models and the Law 8. The Code That Changed the World? Notes Index Abstract The motives of 141 contributors to a large Open Source Software (OSS) project (the Linux kernel) was explored with an Internet-based questionnaire study. Measured factors were both derived from discussions within the Linux community as well as from models from social sciences. Participants’ engagement was particularly determined by their identification as a Linux developer, by pragmatic motives to improve own software, and by their tolerance of time investments. Moreover, some of the software development was accomplished by teams. Activities in these teams were particularly determined by participants’ evaluation of the team goals as well as by their perceived indispensability and self-efficacy. 