How are cookies matched between DSPs like DoubleClick and DMPs like BlueKai for the purpose of ad serving if browser security prevents 1 party from reading the cookie of another party?
From what I've read, the DSP ad pixel would piggyback on the DMPs container tag so that each time the DMP's pixel is called the DSP's pixel is called. At this point, what information can be passed from the DMP to the DSP that allows the DSP to equate its ViewerId to the DMPs ViewerId?
Perhaps, I'm misunderstanding how piggybacking works. Any help is greatly appreciated
Thanks!