No 3rd party ad broker would provide such services, as their preference was to have each ad space on a given website beholden to a single ad provider. This practice limited the potential value of the ad space to the campaigns that a single provider could offer at any given time. The meta-server was able to query all the different ad brokers with whom we had active accounts, and "know" from moment to moment which had available inventory and which were offering the highest rates of pay. Using this allowed us to increase the value of our ad space significantly, also increasing the value of the web property as well.