1. A computer-implemented method for building a brand campaign in a social networking system, the method comprising: receiving, by a computer system from a brand promoter, a budget and brand art for a brand campaign in a social networking system; receiving, by the computer system, one or more target attributes of social publishers in the social networking system, the target attributes selected by the brand promoter to sponsor as part of the brand campaign; prior to activating the brand campaign, estimating, by the computer system and transmitting to a device of the brand promoter, a campaign fulfillment metric comprising a reach and burn rate indicating an expected number of impressions to other members in the social networking system of the brand art based at least in part on the target attributes and the budget, wherein the estimated campaign fulfillment metric is estimated based, at least in part, on a social influence level of social publishers having the target attributes and who are estimated to accept an offer to receive compensation for allowing the brand art to be automatically included within social content of the social publishers having the target attributes; responsive to activating the brand campaign, identifying, by the computer system, a social publisher having the target attributes selected by the brand promoter, the identified social publisher being a member of the social networking system; communicating, by the computer system to a device of the identified social publisher, the offer for the identified social publisher to receive compensation in exchange for the identified social publisher allowing the brand art to be automatically included within social content of the identified social publisher, the social content published by the social networking system; and responsive to receiving from the device of the identified social publisher an acceptance of the offer, causing the brand art to be automatically included within the social content of the identified social publisher displayed to other members in the social networking system.