Usually an Ad Hominem attack is made as a diversionary measure, something to attempt to turn an argument away from conceding a lost point.

In this case, you use an attack – the claim that you’ve been targetted by a “petty, ad hominem attack” – to avoid conceding the truth: “Never once was any direct or indirect measure relating to traffic levels a part of the PageRank algorithm.”

Since you have the paper to hand now to quote, please accept my open invitation to quote the part about traffic.

Petty accusations and slight of hand don’t cut it. I’m rather surprised that you resort to accusations rather than having the maturity and grace to say “okay, it says nothing about traffic, just as you stated”.

Not that surprised anymore though, I guess.

My reference to links measuring traffic levels is based on the following quotation:

“PageRank can be thought of as a model of user behavior. We assume there is a “random surfer” who is given a web page at random and keeps clicking on links, never hitting “back” but eventually gets bored and starts on another random page.”

Evidently, if someone buys links on a dead site that doesn’t get traffic anymore – as is the case for many indexed but non-ranking sites – or else buys offtopic links that won’t get clicked on (because they’re not contextual), then according to that paradigm, Google wouldn’t count those paid links.

As to counting citations, the following quotation from the same part of the paper seems to highlight what you mean.
“Another intuitive justification is that a page can have a high PageRank if there are many pages that point to it, or if there are some pages that point to it and have a high PageRank. Intuitively, pages that are well cited from many places around the web are worth looking at. Also, pages that have perhaps only one citation from something like the Yahoo! homepage are also generally worth looking at. If a page was not high quality, or was a broken link, it is quite likely that Yahoo’s homepage would not link to it. PageRank handles both these cases and everything in between by recursively propagating weights through the link structure of the web.”

I think that shows Google already understanding that not all citations were created equal from the get-go.

So, with all due respect – as having seen your name around in reputable circles, I know you’re a leading SEO – I don’t think your criticism stands up.

Never once was any direct or indirect measure relating to traffic levels a part of the PageRank algorithm. Instead, it was modelled directly on a method for predicting the winner of the Nobel prize by counting citations in other science papers.

Citations.

Citations are what PageRank was always based upon. All that has changed over the decade since is that Google, (like the rest of us) worked out that some citations were more valuable and ‘genuine’ than others based upon more than just how many citations the publisher of a citation themselves had.

Google discovered that authors could be bribed into citing one source over another, or in simply citing a source they would not otherwise have cited at all.