Wheeeee. Google updates PR numbers in the toolbar every few months, and another update is happening. The numbers on the toolbar don’t represent anything that Google uses for rankings in its algorithm, except in an abstract way. The hip thing to do if you’re an SEOer is just to ignore it. I have the Google toolbar installed on my browser, and I still look at the numbers. Here’s what I use the numbers for:

1. Get a general idea if Google’s spider sees a page or counts it for anything. In particular, I look out for the grey bar.
2. Get a general idea of whether a page has links or whether a page is linked to from other pages that have links.
3. Show clients that, indeed, I have gotten their site some new links, pointing out an increase in toolbar PageRank.

Of course, you always have to consider the limitations of the toolbar: it isn’t updated often, and it doesn’t represent overall link popularity (just to name a couple of major items among plenty of other quirky limitations). In particular it doesn’t measure the relevance of links to a site. All of the three points above, I back up with other methods. To see if a page is visible or a candidate for rankings (point 1), I’d also search Google’s index for a page in question and see if there’s anything cached for the page. To see if a page has good links (point 2), I might spend time looking up links to a page in Yahoo! Site Explorer, check out the links to the domain as a whole, or try to find the other pages that link to the page in question. To show clients the results of hard link building work (point 3), I might show a list of places I’ve requested links from and also show link results from Google Webmaster Tools and Yahoo! Site Explorer. Preferably, I’d just be showing a client increases in traffic, leads, and sales instead of going over details about links. So the toolbar PageRank really isn’t that important.

The topic has pretty much been beaten to death by the SEO community. Part of the reason is people become fixated on it; it’s like Google is giving your website a grade. Just about everyone I know enjoys reducing people, websites, complexity, and work-effort to a letter or number, so the appeal is definitely there as far as I can see, and it’s a great marketing tool for Google.

If you’re new to search engine optimization, I still recommend taking a look at PageRank numbers. It gets you thinking about websites in a different way, concerning how links are important, how PageRank gets passed on to other pages, and how pages visible to you may not be visible to a spider. But I also recommend not getting caught up in the numbers and not using the toolbar for final or serious judgments about a site or page. It’s also worth noting that if you enjoy your privacy, you might not want to download the toolbar for viewing PageRank.

For more information about the toolbar update, visit SearchEngineLand.com, a great place for SEO information.