Abstract: The present invention relates to certain bidding and ranking systems, which may be used to rank objects in a computing environment, such as, for example, bidding and ranking systems that may be used to rank on-line advertisements. According to certain embodiments of the invention, such methods of ranking objects comprise receiving input values from a plurality of users. Each input value is preferably correlated with an object during a defined time interval, and each object is associated with a single user. The method further comprises calculating a sum of the input values associated with each object at defined time points, and then ranking each object, at each time point, based on the sum of the input values associated with each object.