Based on a four-year study of the Common Knowledge: Pittsburgh (Pennsylvania) project--one of four national "testbeds" for the exploration of the Internet's potential for improving education, this paper explores the factors that delayed, shaped, and constrained Internet use in a large urban school district. Although a substantial amount of use occurred, problems in interfacing with the district's pre-existing physical infrastructure, its bureaucratic procedures, and the culture of its schools all influenced use markedly. Infrastructure problems included difficulties retrofitting old buildings, including asbestos in school walls, and lack of needed power outlets, space, and furniture. Bureaucratic problems included incompatibility between rigid bell schedules and the unpredictability of access to Internet sites. Finally, cultural factors including the teachers' role as dispenser of knowledge, the image of a well-run classroom as one in which students sit quietly in their seats, the tendency to emphasize basic skills and to conceptualize learning along disciplinary lines, and concerns about ensuring that the materials students access in school are consistent with community beliefs and standards also shaped and limited Internet use. Contains 10 references. (Author/AEF)