Problem statement

The RTB traffic between SSPs and DSPs incurs hardware costs to all participants (networking and processing) as well as leads to extra CO2 footprint. Today many SSPs prefilter traffic to DSPs based on the user sync status – the knowledge of the 3P cookie ID presence for the given imp opportunity. 30%-60% traffic optimization depending on the DSP trading specifics.

With the cookie deprecation and in the current PAAPI setup such optimization doesn’t work. The SSP loses knowledge on whether the user has a DSP cookie and thus is potentially interesting for the DSP for bidding, and therefore the SSP is unable to effectively prefilter traffic for IG bidding. Unless somehow managed, this setup will result in about 30%-60% of redundant bid request and bid response traffic between the SSPs and DSPs.

Proposal

It is fair to say that the DSP is potentially interested in bidding for a given in-browser impression opportunity if there is at least one active Interest Group of theirs in the target browser. And in order for the SSP to make RTB traffic distribution decision they need to know which DSPs are potentially interested. To achieve that it's proposed to extend the bid opportunity data passed by the browser to the SSP with a list (an array) of unique origin domains of the active Interest Groups in the browser.

Privacy concerns

As no information about the actual Interest Groups is passed to the SSP (and as a result to other RTB players), there doesn’t seem to be any risks or concerns from the user privacy perspective. Yet for even a higher level of privacy we can afford to add a few ‘noise’ origins to the list, different on every request – even the salted list should be a huge help for the traffic shaping/optimization logic on the SSP side.