I think those buying advertising know that the ad networks' metrics are hopelessly broken, that fraud is rampant, and that their actual impressions are far less

I think those buying advertising know that the ad networks' metrics are hopelessly broken, that fraud is rampant, and that their actual impressions are far less than reported. But the problem is pervasive and spans the entire ad industry, so what are they to do, other than throw in as much money as possible and hope for the best? I recently saw a comment (can't remember where) from someone involved in an advertising startup ostensibly focused on serving unintrusive ads with accurate reporting, and the response has been overwhelmingly positive: ad buyers expressed profound relief at seeing ad metrics that actually made sense. I don't think we can make too many assumptions about how spending would change if ad metrics were actually accurate, simply because the current metrics are so bad, and the impressions so fraudulent, that the current ad spending is largely uninformed. If the metrics were accurate, ad buyers might very well end up spending less while getting more for their money, because they can suddenly make informed decisions.