Cases have been used in education through a variety of methods, such as case written analysis, case discussion, and case development. Recent case definitions and uses have extended their traditional uses. In case-based reasoning, cases are considered to represent knowledge, and the use of cases is integral to an individual's problem-solving process. Case-based activity (CBA) builds on CBR research and theory, emphasizing the transition of novices toward experts' reasoning and applications. The purpose of this paper is to present the theoretical assumptions and principles for designing grounded, web-enhanced CBA. Findings from recent implementations and implications for design are presented.