Not all the benefits of advertising can be directly tracked from click to sale. If you buy a banner on TechCrunch and don't make your money back on direct sales

Not all the benefits of advertising can be directly tracked from click to sale. If you buy a banner on TechCrunch and don't make your money back on direct sales but everyone interested in startups has heard of your product, that is not necessarily a loss. Also the author was not suggesting that we switch from CPM to CPC/CPA: "CPA and CPC have their appropriate time and place, but let’s recognize that those situations are limited." He is advocating the development of new advertising metrics that are more closely aligned with engagement and other marketing goals that have nothing to do with sheer impressions.