1. A method comprising: receiving, by an online publication system, information that includes the identity of a merchant and one or more products sold by the merchant, and preferences of the merchant; using the information to publish an advertising campaign across a plurality of communication channels; in response to determining that at least one first communication channel of the plurality of communication channels satisfies factors regarding a preference of the merchant for advertisements focusing on the merchant's identity, providing merchant-centric advertisements via the at least one first channel; and in response to determining that at least one second communication channel of the plurality of communication channels satisfies factors regarding a preference of the merchant for advertisements focusing on the one or more products sold by the merchant, providing product-centric advertisements that are different from the merchant-centric advertisements via the at least one second channel.