This article reports on work studying how technology can empower or exclude its users due to interactions between social context, system design, and implementation. The analysis is based around the introduction and use of digital libraries in four different settings, three clinical and one academic. Across the four settings, in-depth interview and focus group data was collected from 144 users and analyzed with reference to “communities of practice”. The four settings represent three different approaches to digital library implementation: making digital library resources available from existing computer systems in people's offices and the library (a traditional approach); making computer systems, and hence digital libraries, available in shared spaces (in this case, hospital wards); and employing information intermediaries to work with staff and library resources. These different approaches engendered different perceptions of the technology. The traditional approach produced perceptions of technology as being irrelevant for current needs and community practices. Making technology available within shared physical space but with poor design, support, and implementation procedures was widely perceived as a threat to current organizational structures. In contrast, technology implemented within the community which could adapt and change practices according to individual and group needs, supported by an information intermediary, was seen as empowering to both the community and the individual. We relate the findings to a discussion of evolutionary and revolutionary approaches to design and to the concept of communities of practice.