1. A computer system for targeted advertising in a computer network of users, the computer system comprising: an advertisement database storing advertisements indexed with respective targeting criteria; and at least one computer coupled to a global network of client computer devices, each client computer device associated with at least one of a plurality of users, the plurality of users dynamically forming connections with other users resulting in an interconnected computer based social network, the at least one computer being configured to: determine a rank for each of the plurality of users within the interconnected computer based social network as a function of user demand and user importance, said determining including deriving the importance of each user as a function of user demand within the interconnected computer based social network, such that the rank of each user is determined after one pass of iterations by determining a product of a first data structure and a second data structure, the first data structure being based on and representing connections between the plurality of users within the interconnected computer based social network and the second data structure being based on a number of the plurality of users within the interconnected computer based social network, monitor Internet activity of a given user of the plurality of users and determine keywords from the monitored Internet activity, in response to receiving a request associated with the given user, construct a query including the determined keywords and the determined rank of the given user to retrieve at least some of the stored advertisements for display, retrieve at least some of the stored advertisements from the advertisement database according to the constructed query, prioritize the retrieved advertisements, and cause the retrieved advertisements to be displayed on the client computer device associated with the given user based on the prioritization.