Abstract. We think that over the next few years, the goal of interactive systems and services will evolve from just making systems easy to use (even though that goal has not yet been completely achieved) to making systems that are easy to develop by end users. By now, most people have become familiar with the basic functionality and interfaces of computers, but they are not able to manage any programming language. Therefore, they cannot develop new applications or modify current ones according to their needs.In order to address such challenges it is necessary a new paradigm, based on a multidisciplinary approach involving several types of expertise, such as software engineering, human-computer interaction, CSCW, which are now rather fragmented and with little interaction. The resulting methods and tools can provide results useful across many application domains, such as ERP, multi-device services (accessible through both mobile and stationary devices), and professional applications.Key words. tailorability, end user programming, flexibility, usabilityWe think that over the next few years, the goal of human-computer interaction (HCI) will evolve from just making systems easy to use (even though that goal has not yet been completely achieved) to making systems that are easy to develop. By now, most people have become familiar with the basic functionality and interfaces of computers. However, developing new or modified applications that effectively support users' goals still requires considerable expertise in programming that cannot be expected from most people. Thus, one fundamental challenge for the coming years is to develop environments that allow users who do not have background in programming to develop or modify their own applications, with the ultimate aim of empowering people to flexibly employ advanced information and communication technologies.Current trends in professional life, education, and also in leisure time are characterized by increasing change and diversity: changing work and business practices, individual qualifications and preferences, or changes in the dynamic environments in which organizations and individuals act. The diversity concerns people with different skills, knowledge, cultural background, and cognitive or physiological abilities, as well Henry Lieberman et al. (eds.), End User Development, 1-8. C 2006 Springer.