There is provided a method of providing a ranked list of computer-implemented activities to a user. As a performed activity is received, a plurality of lists, which each of the lists defines a ranking of activities, is accessed. The rankings of different lists are calculated with respect to different time horizons. The positions in the lists are associated with scores which are updated in view of the received activity. Also, the rankings of the lists are updated in view of the received activity. The lists are then combined into a single list. The combination is based on the updated lists and the scores associated with the positions in the lists.