Abstract: An example process includes: obtaining information about call-outs from at least one bidder of an online content auction, where the information spans a time period and the information identifies which call-outs, within the time period, did not result in a response; identifying, based on the information, one or more features that are common to call-outs that did not result in at least a threshold number of responses from the at least one bidder; generating a model for the at least one bidder that predicts whether the at least one bidder will respond to a call-out associated with the one or more features; using the model to determine a percentage of additional call-outs having the one or more features to send to the at least one bidder; and sending the percentage of additional call-outs to the at least one bidder.

Abstract: An example process includes: obtaining information about call-outs from at least one bidder of an online content auction, where the information spans a time period and the information identifies which call-outs, within the time period, did not result in a response; identifying, based on the information, one or more features that are common to call-outs that did not result in at least a threshold number of responses from the at least one bidder; generating a model for the at least one bidder that predicts whether the at least one bidder will respond to a call-out associated with the one or more features; using the model to determine a percentage of additional call-outs having the one or more features to send to the at least one bidder; and sending the percentage of additional call-outs to the at least one bidder.

Abstract: A method includes receiving, from one or more publishers having an associated inventory of one or more content item slots, (i) a first identifier specified by the one or more publishers and associated with the one or more publishers and (ii) a second identifier specified by the one or more publishers and associated with the inventory of content item slots, wherein the first identifier is associated with a branding tier. The method includes receiving a request for a content item associated with the inventory of content item slots; and in response to the request, performing a content auction, including providing the first identifier, the second identifier, or both, based on the branding tier.