Permanent involvement of end users in software development is both highly recommended and highly challenging. Against the background of our results and experiences from two research projects, we summarize several key issues and design concerns that need to be considered when integrating users and their feedback into software development. Categories and Subject Descriptors K.6.3 [Software Management]: Software development. D.2.1 [Requirements/Specifications]: Elicitation methods. D.2.2 [Design Tools and Techniques]: User interfaces. H.5.2 [User