This chapter discusses typical collaborative requirements definition processes as they are performed in open source software development (OSSD) projects. In the beginning, some important aspects of the entire OSSD approach are introduced in order to enable an understanding of the subsequent description of the feedback-based requirements definition processes. Since the OSSD model seems to represent a successful way of dealing with the significant distribution and heterogeneity of its actors, some opportunities to adapt this approach also in other (software) industries are discussed. Nevertheless the entire OSSD model still exhibits several improvement opportunities that also are addressed in this chapter. In order to overcome possible weaknesses, several approaches to improve the described requirements definition approach are introduced. These improvements help to assure a higher level of efficiency and quality assurance for both processes and the developed artifacts, and furthermore also enable the consideration and acceptance of this approach in other domains and industries.