Header bidding systems and methods increase a number of advertisers that can place bids for an advertising impression while maintaining low latency in loading of the webpage, while still permitting control for reporting and review of inappropriate advertising content. Even though advertising content may be received from a plurality of disparate advertising sources, information identifying the source of each advertisement is maintained such that when an advertisement is reported as inappropriate, information regarding the advertisement and the source of the advertisement is gathered and delivered to a review system, such that when advertisements are in fact deemed inappropriate, the correct advertiser can be notified and future display of the inappropriate advertisement blocked.