“Psychologists have studied ‘optimal human experience’ for many years, often called ‘being in the flow’. Through years of study, the basic characteristics of flow have been identified. This paper reviews the literature, and interprets the characteristics of flow within the context of interface design with the goal of understanding what kinds of interfaces are most conducive to supporting users being in the flow. Several examples to demonstrate the connection to flow are given.” (Benjamin B. Bederson – ACM Ubiquity)