The open source movement is affecting software development products and processes. Software products benefit from reusable elements’ increased availability and flexibility but might suffer from tighter coupling and more complex dependencies between reused components. The software development process is gaining from the widespread availability and use of sophisticated open source development platforms and tools, and the adoption of corresponding development and coding practices by the programmer community. In addition, code as literature is helping the meaningful education of programmers. However, process integration and the coevolution of multiple open source and proprietary projects are still open problems.