Secondly, a much bigger issue is that almost all buyers are ignorant of DSP throttling, which influences 99 out of 103 DSPs we know of. Except for the largest gamers, most DSPs cannot afford to acquire all of the bid requests that come via exchanges. The average exchange sends tens of thousands of bid requests a second and it costs DSPs a few penny CPM to system each bid request. To cut costs, DSPs enable throttling by putting a query per second QPS cap on the number of bid requests that they can obtain from each trade.
QPS is a blunt tool with high collateral damage. Because the exchanges don’t know which of the user IDs belong to the buyers’ desired audiences, throttling removes both the “in target” and “out of target” user IDs at approximately an analogous proportion. As a result, the number of “in target” requests sent to DSPs is significantly cut, inflicting the dimensions of viewers focused campaigns to suffer dramatically.