1. A system for promoting expansion of a social network, the system comprising: a server computer supporting a social network; computer program code, communicatively coupled to the server computer, the computer program code, when executed, causing the server computer to: determine a social relationship between a primary user of the social network and a number of other users of the social network based on comparing data for the primary user with data for the other users of the social network; determine an obscurity level for each of the other users based on the social relationship for each of the users relative to the primary user; present a social network map showing a representation of the primary user and the number of other users of the social network, wherein a strength of the determined social relationship between each other user and the primary user is indicated on the social network map; and obscure the representation of at least some of the other users based on the determined obscurity level by reducing visibility of at least parts of the social network map so as to obscure identity of at least some of the other users represented on the social network map.