1. A system for cross-population of virtual communities, the system comprising: a communities module stored in memory and executable by a processor to provide a plurality of virtual communities, each virtual community comprising an activity module configured to provide access to content within the virtual community; a relationships module stored in memory and executable by the processor to: manage user access to the plurality of virtual communities based on a cross-population relationship between the plurality of virtual communities, wherein the cross-population relationship allows a member of one of the virtual communities in the cross-population relationship to access another virtual community in the cross-population relationship, and provide the user with content from the first virtual community or from the second virtual community based on a niche of the first virtual community and a secondary profile of the user; and a profile module stored in memory and executable by the processor to store a profile of each of the users.