A social pyramid is a model of social people. The people with whom an individual has the least amount of social intimacy are placed at the foundation of the pyramid. At the top of the pyramid is the individual. And on each subsequent layer going down, the individual has less and less intimacy. For example, the person you interacted with while in line at the grocery store is at the base of your pyramid, but your spouse or lover would be very close to the top.
It has been said that the what one brings to one's [social network] is what one creates with one's social pyramid.