In writings on the open source software development model, it is often argued that it is successful as a result of the gift economy that embraces activities in online communities. However, the theoretical foundations for this argument are seldom discussed and empirically tested. Starting with the 'classic' theories of gift giving, we discuss how they need to be developed in order to explain giftgiving practices in digital domains. In this paper, we argue that the gift economy is important, not only because it creates openness, but also because it organizes relationships between people in a certain way. Open source software development relies on gift giving as a way of getting new ideas and prototypes out into circulation. This also implies that the giver gets power from giving away. This power is used as a way of guaranteeing the quality of the code. We relate this practice to how gifts, in the form of new scientific knowledge, are given to the research community, and how this is done through peer review processes.