I hadn't considered this article's perspective before, but I think it is very compelling. A lot of commenters (and likely readers) are probably focusing heavily on the perceived impact of the "fraud" of reporting X amount of impressions and/or clicks, when only Y amount of them were "real." They feel like they are paying for X but only getting Y. I think the simple point this article effectively made is that ad companies have continuously reduced prices so that their clients are actually only paying for Y, or at least they are benefiting from a discount which observes the uncertainty.

I think the basic assumption has been that, even though we know the total number of "impressions" is exaggerated, the number is correlated with the "real" number. So long as that assumption is usually true, this is no more a case of fraud than Airlines' reward "miles".

To be fair though, larger clients who blanket the web with ads for a campaign have the advantage of spreading the risk over a large number of websites and times. The people most impacted by impression-based ad runs are those who can only afford the smallest campaigns.