: Even though end-user participation in requirements engineering (RE) is highly important, it is at present not frequently used. Reasons can be found in the large expenditure of time for organizing and carrying out surveys as well as in the time it takes to understand the users' requirements. This research is supposed to address this problem by presenting the OpenProposal approach for distributed user participation using visual requirement specifications. Additionally the research agenda is being outlined for developing and evaluating methods and tools for collaborative end-user participation in Requirements Management (RM). The experiences gathered during this research were promising.