We consider a crucial aspect of displaying advertisements on the internet: the individual user. In particular, we consider ad fatigue, where a user tires of an advertisement as it is seen more often. We would like to show advertisements such that, given the impact of ad fatigue, the overall efficiency of the system is optimized. We design an approximation algorithm, for the case that we study, that approaches the optimum as the number of unique ads shown, if there is only one available position, increases.