There are so many flaws in this argument. First of all it doesn't apply to the vast majority of communications efforts, since it only works on pages where the circulation figures are readily available. It will never tell you how much a mention on influential blos like Shel Israel's blog is worth, or the value of a Tweet by GeekMommy because they don't have published advertising rates.
Secondly, this system bases its entire calculation on numbers provided by Alexa which is the least reliable of the various panel-based systems. Alexa was initially shipped with many new Vista computers, but because it was immediately blocked by most spam filters, most people stopped using it.
Finally, what's the point? Why would I bother doing arcane math to compare my efforts with an outdated model, when I can use a unique URL to directly measure the sales impact of my efforts.