19. The system of claim 18 , wherein the document factor module is configured to calculate for each of the two or more contributors a document factor that represents a quantified cumulative value of contributions of the contributor to documents in the knowledge base.
19. The system of claim 18 , wherein the document factor module is configured to calculate for each of the two or more contributors a document factor that represents a quantified cumulative value of contributions of the contributor to documents in the knowledge base. 26. The system of claim 19 , further comprising a contributor network module to maintain follower networks that are indicated by the personal network information, each structured follower network comprising one or more followers who are registered to follow a target contributor.