Optimal, or flow experience is a psychological construct introduced by M. Csik-szentmihalyi; it refers to intrinsic motivation when an activity is worth doing for its own sake and denotes productive work with high concentration on the task, distinct objectives and high level of satisfaction, positive feelings such as enjoyment, balance between the available skills and the task challenges, immediate feedback, as well as temporary loss of self-consciousness and distorted sense of time. This construct is being intensely used in numerous environments connected with the use of information technologies, including specific ones such as Internet addiction. The latter context is argued to be incorrect, since addiction means a negative feeling while flow is positive. Numerous examples follow distinguishing online gamers' repetitive behaviors referring to flow experience from those which refer to addictive behavior.