The upward trend in the sector of the digital games goes on.An evolution takes place, which is capable to go to many directions. On the one hand computer graphics become more realistic, games are more complex and the speed, as well as the distribution, of the internet increases steadily. On the other hand another trend appears: browser-games, also called MMOGs (Massive Multiplayer Online Games). Games, which are text-based or contain only few graphical content and are playable without local installation on the computer. Only an internet connection and a browser is needed to use them. These persistant online-worlds, in this special case a browser-game called "Space Merchant Realms", are the object of investigation in this work. Before the empirical analysis is proceeded, the object of investigation is defined in the sector of computer-games and online-games. Subsequently the identification of usagemotivations, gameplay experience and playing-behavior is, as well as its temporal variation, in focus. In this longitudinal research, the usage-motivations are examined with help of the Uses-and-Gratification-Approach and the gameplay-experience is examined with the flow-theory. In two waves of the questionnaire (Nt0=125; Nt1=135), which were surveyed at an interval of ten weeks, several results could be extracted. Ten game motivation factors (total variance 67,175%) and four game experience factors (total variance 58.5%) appeared by the usage of factor analysis. Based on self-evaluation of players, further statements on playing-behavior could be encountered. Moreover the variations of usage-motivations, gameplayexperience and playing-behavior after ten weeks were determined. Four of the ten motivationfactors arose (one of these significant), while six factors stayed constant. Three of the experience-factors became less important (one of these highly significant) and one remained constant. The time of usage demonstrably decreased within ten weeks. This investigation which claimes to be a kind of pilot study, is the first step into an integrated investigation of browser-games.