Last week, I got asked what the big deal about PageRank changing was. I said it was because it only changes every few months. Turns out I was wrong, but I had no way of verifying one way or the other.

Matt Cutts, the guy who works at Google, and explains SEO issues simply for the masses (read you and me), explains some stuff about PageRank. Here's the answer a person who doesn't work at Google wouldn't have any idea about, and it's helpful to know:

I believe that I've said before that PageRank is computed continuously; there are machines that take inputs to the PageRank algorithm at Google and compute the resulting PageRanks. So at any given time, a url in Google's system has up-to-date PageRank as a result of running the computation with the inputs to the algorithm. From time-to-time, that internal PageRank value is exported so that it's visible to Google Toolbar users (see the question below for more details on the timing).

In other words, Google keeps track of your PageRank internally all the time, but it's exported to the Google Toolbar only every once in a while. That's nice to know, but it sure would be nice if it exported a little more often, mainly for the 4, 5, and 6 sites, as the change from those is significant. Here at the Wizbang Network, we still get thousands of Google searches a day, and the main blog has a PageRank of 7, so you figure out how that works.

(As an aside, I've got a site that gets most of its traffic from Google searches, and it showed up as a PageRank 0 last week, yet it's obviously ranking far much higher than that. Today it shows as a PageRank 5, where I'd expect with the amount of search engine traffic.)