1. A method for generating an electronic communication, the electronic communication comprising a plurality of content slots for displaying content relating to one or more items, the method comprising: providing the plurality of content slots for inclusion in the electronic communication, each of the content slots defining a region within the electronic communication into which content may be displayed by at least one of a plurality of content generators; determining, using a processor, one of the plurality of content generators for providing content to at least one of the plurality of content slots, wherein each of the plurality of content generators comprises assignment preference logic for selecting from among a plurality of sets of content, and wherein the determining the one of the plurality of promotion content generators comprises: providing at least a first content generator of the plurality of content generators with a set of selection parameters; receiving a first bid for a first one of the plurality of content slots from the first content generator, wherein the first content generator determines the first bid based at least in part on the set of selection parameters; and assigning the first content generator to the first one of the plurality of content slots based at least in part on the first bid, the first content generator providing preliminary content for display in the first one of the plurality of content slots, the preliminary content selected by the first content generator from among the plurality of sets of content based at least in part on the set of selection parameters and assignment preference logic of the first content generator; determining a display content for each of the plurality of content slots based on comparing the preliminary content to one or more electronic communication rules; generating the electronic communication based on the determined display content; and transmitting the electronic communication.