Parting the Curtains of Google’s Ad Display Network

Craig Silverman and Ruth Talbot, ProPublica:

ProPublica spent months trying to crack open Google’s black box ad business. We wrote thousands of lines of code to scan more than 7 million website domains looking for Google ad activity, sourced and analyzed data on millions more domains from half a dozen data partners, and spoke to some of the most knowledgeable experts about Google’s display ad business.

In the end, we matched 70% of the accounts in Google’s ad sellers list to one or more domains or apps, more than any dataset ProPublica is aware of. But we couldn’t find all of Google’s publisher partners. What we did find was a system so large, secretive and bafflingly complex that it proved impossible to uncover everyone Google works with and where it’s sending advertisers’ money.

This report builds upon an October investigation from Check My Adspreviously linked — and it reveals how Google’s power and scale do not meaningfully reflect the trust of advertisers. There is, perhaps, an argument to be made for putting space between ad buyers, sellers, and placements, similar in spirit to the way media separates its business side from its journalism side. But that would require Google to display dilligence at a level it is either incapable of or unwilling to do in all parts of its advertising business. Judging by the quality of ads I see on Google’s own properties like YouTube, it seems monitoring ads at scale would preclude that level of confidence in buyers or sellers.