Jason Calcanis posts a lengthy analysis of the concept of Cost-Per-Influence (CPI) as it relates to advertising on lower-traficked but arguably influential blogs. In typically blunt fashion, Jason takes the argument for CPI down a notch:

Online advertising is about performance first and image second.

John knows this better then anyone because he created/helped produce two of the best looking and well done business/tech magazines in history: the Industry Standard and WIRED. The advertisers knew how influential these magazines were without a CPI index. Again, advertisers get it… they don’t need a CPI index.

To be blunt, as I’m prone to be, the CPI concept is appealing to those folks who don’t have the traffic to back up the claim that they are influential or who don’t want to wait till their traffic reaches that level. It also appeals to those who don’t have the ability or time to demonstrate to advertisers that they are influential.

As someone who has evaluated blog-based advertising for some of my campaigns in the past year, I’d have to agree with the bulk of Jason’s comments. It’s a commonly accepted idea, at least in tech marketing, that blog readers tend to be the more influential of your customers. Therefore a major goal of advertising on blogs is not so much to generate mass conversions, but to generate the right conversions.