When building information systems that can be accessed through desktop and mobile devices, developers often face the same basic design decisions that depend on a number of still unstructured criteria. Going through the whole decision-making process for every project is inefficient and error-prone, however, a comprehensive set of best practices has not yet been established. We therefore present the foundations of a classification scheme for mobile commerce systems that helps developers to categorize applications according to high-level requirements. After a discussion of the criteria, we suggest implications that can be drawn from it and present examples for their application.