This article offers a theoretical analysis of evolutionary processes in WBSS strategies. For that purpose, we propose a research model that shows strategy patterns. Based upon the model, we identified several types of strategies. In our research model, WBSS are classified into four types: (1) general-direct-sales (GDS); (2) general-intermediary-sales (GIS); (3) specialized-direct-sales (SDS); and (4) specialized-intermediary-sales (SIS). On the basis of these four categories of WBSS, we analyze the characteristics of WBSS and suggest five evolution strategies for WBSS, which have implications for both theory and practice. Amazon.com's strategic movements, such as product line expansion through alliance and acquisition, provide an exemplary case of the evolution of WBSS strategy. We expect that this research will serve as a guide for Internet businesses and as a catalyst for new research agendas relevant to Web-based shopping and electronic commerce.