Ad exchanges do not usually charge the sites. Ad exchanges usually charge a fixed rate on revenue (like 15% or 20%). If the spend is the same, then the ad exc

Ad exchanges do not usually charge the sites. Ad exchanges usually charge a fixed rate on revenue (like 15% or 20%). If the spend is the same, then the ad exchanges don't make any more money. There are other middle men, like the audit companies and the impression counters, but they end up making less money because they usually charge by the volume of impressions: Since the same budget will be spent over a smaller number of sites, the prices for those sites will raise and the number of impressions will go down. The only people who win are the publishers of those sites who now have more money for the same users.