An in-depth understanding of human factors in web-based interaction requires a methodology which enables researchers to chart online actions, understand the cognitive processes guiding these actions and the mental dispositions governing them. In this regard, the self-confrontation interview is an extremely effective method. In this article, the self-confrontation interview method, its history, design and execution are explained. This method was utilized in a study on online shopping behavior. Selected findings from this study are presented and design principles which will enhance the usability of online store interfaces are proposed. These design principles are: (i) follow a sequential progression, (ii) mimic real-life scripts, (iii) provide visual indicators, (iv) place functionality above aesthetics and (v) avoid conditioning automatic actions. The article concludes with an assessment of the strengths and limitations of the self-confrontation interview method and its efficacy vis a vis other methods of studying web-based interaction.