Few attempts to classify adopters of e-commerce have been published in research, even though such classifications enable adopter profiling for marketing campaigns and governmental intervention projects. Overall, earlier studies of e-commerce adoption have often failed to consider the situation surrounding the adoption. Without information on the contexts in which specific drivers or barriers occur, the usefulness of these findings is limited. In this study, a typology over adoption triggers for e-commerce in Small and Medium-sized Enterprises (SMEs) is assessed and enhanced by the case studies of three SMEs. As a result five, 'adoption situations' are proposed. An adoption situation describes a company's disposition to the adoption of e-commerce and the contextual features that foster them. Five categories are identified; proactive adoption, adaptive adoption, pragmatic adoption, forced adoption and enabled adoption. Moreover, factors that determine which adoption situation a company tend to end up in are proposed. These are the relative dependence on individual trading partners, the degree of customer pressure, the company's strategic and structural needs of e-commerce, and the CEO's attitude towards risk taking. The study is theory-building in its nature and the contributions need to be tested empirically in future studies.