The publisher has the same ability to vet the advertisement that a subcontractor delivery, that a company has to vet the construction material when subcontracting the construction of a building. If publisher were held responsible, they would only deal with advertisement network that are held economically responsible if advertisement they deliver breaks the law. That mean higher costs, less revenue, but an end to the wild west we currently have.<p>If I buy a paper based newspaper, the ads on those follow a very strict set of local laws. Each time an illegal ad is mistakenly printed, its news that other papers just love to write about. If I buy a online subscription, none of this laws are in place, and to the same large number of 9s-decimal places that you talk about, the illegal ads will be on the online version.