With the increasing number of websites that have found their way into our daily lives, substantial resources are invested in enhancing user experience beyond mere functionality. Optimizing flow-the psychological state of deep focus while conducting a fluent activity-seems a promising approach, resulting in a win-win situation for both users and website operators. Flow has been found to result in "optimal" user experience leading to intrinsically motivated behavior, engagement, and loyalty. However, to date, there is little concrete knowledge of or advice on how to design a website for flow. This study develops a grounded theory of flow experiences in the context of online shopping, and sheds light on the theoretical relationships between concrete realizable website design options, corresponding latent constructs, and flow experience. Based on our findings we derive theoretical as well as practical implications for understanding and designing flow experience on the web.KEY WORDS AND PHRASES: Flow theory, digital service innovation, user experience, human--computer interaction, e-tail, grounded theory.The point that information systems' use can be a source of pleasure has been increasingly emphasized for several decades by researchers in the field of information systems research and human-computer interaction (e.g., [7,48,81]). In this context, pleasure or enjoyment addresses "the extent to which the activity of using the computer is perceived to be enjoyable in its own right, apart from any performance consequences that may be anticipated" [18, p. 1113]. Similarly, motivations to engage in information search that include both utilitarian and hedonic dimensions provide an expanded view on e-commerce that has been increasingly examined in the past decade (e.g., [5,12,65]). In the same vein, the theory of flow has been proposed by various authors as a useful framework to explain user behavior (e.g., [15,22,23,24,31,37,75,82]). Flow describes the state of "self reflection-free immersion in a continual activity" [70, p. 380] in which time, place, and an activity's original external aim are forgotten and the individual is totally absorbed in the activity [14,71]. Flow experiences are related to pleasant, intrinsically motivated activities that are usually experienced as very positive [14,54].Examining flow experiences on the Web seems to be particularly promising, since numerous positive side effects are expected if users surf the Web or a website in a state of flow. The experience of flow is positively related to the affect toward websites [59,60], the attitude toward websites [74], satisfaction with websites [19,47], the evaluation of websites [57], and e-learning success [29]. Flow is associated with a website's usefulness and ease of use [2,30,34,74], as well as the intention to use a website [74].are achieved if users surf the Web in a state of flow, resulting in a win-win situation for users and website operators, it seems to be particularly relevant to design websites in a manner that enhances users' flow exper...