In addition to the impact that open source software is having on the information technology market, it is also producing many contributions in the field of software development. For instance, according to the classic concepts of software engineering, only a centralized management and a strong control on the access to the source code permits a good, high quality software product. But this assumption has been at least partially defeated by the success of several open source projects, where a large number of developers spread around the world loosely collaborate to build reliable and high quality software products. Rigorous management and a clearly defined design were also considered instrumental in a successful coding project. This view has also been dispelled in practice by the many open source software projects that have succeeded even without a clean initial design and without a formal management process.