1. A computer system for determining a serving area of a web resource based on addresses of users, the serving area representing a geographic area that is a reach of the web resource, comprising: an access information store that includes, for each access of the web resource, the address of the user who accessed the web resource; an address mapping component that maps an address of the access information to a location within a hierarchy of locations; and an identification component that identifies a location of the hierarchy as a serving area of the web resource based on the number of accesses of the web resource by users within that location and based on the spread of the number of accesses of the web resource by users within locations that are hierarchically within the location.