I’m guessing that this paper was only the basis of Google, the beginning theory…I’m sure Google has evolved quite a bit since that paper was written. Nevertheless, it’ll give you a good understanding of the theory behind PR.  In a nutshell, PR is a calculation of “backlinks”…or…how many other web sites are linking to your site…and not just how many other web sites are linking to you, but the quality of those web sites.
If you have ten PR 2 web sites linking to you, that’s not as good as one or two PR 4 web sites linking to you. So you want to have high PR web sites linking to you (though there’s nothing wrong with having low PR sites linking to you too….high PR sites are better, but low PR sites are better than nothing).
Google PR is based on democracy…every web site that links to you is considered a “vote” for your web site. The site with the most “votes” gets ranked higher. Makes sense right?Google figures that if a whole bunch of web sites (especially high PR web sites) link to you, your site must be good….they wouldn’t link to you if your site was lousy, would they? Well, that’s the logic behind it at least.

So how do you figure out what your web site’s PR is?
To determine your web site’s PR, you need to install the Google Toolbar. It’s a web browser add-on that will show you the PR of every site you visit.
To get the Google Toolbar, go here: http://toolbar.google.com/
You can download the Google Toolbar there for free. The PR feature is an “advanced feature” of the toolbar…so right when you start installation, it will ask you if you want to: “Enable Advanced Features (anonymous information will be sent to Google)”.
You’re going to need to make sure you click that button to enable the advanced features (ie the PageRank tool).
Once you install the Toolbar you can open your web browser and you’ll see it sitting right there at the top of your browser. You can click the “options” button and customize things if you want (that’s where you can disable the pop-up blocker that comes with the toolbar – which I recommend you do).
Once you’ve installed the Google Toolbar, you’ll see a little green bar at the top of your web browser that looks like this:

See that little green bar with the word PageRank over it? If you put your mouse pointer over that little green bar, you’ll see the PR of the site that you are currently visiting. That’s your site’s PR.

Now it’s important to note, Google only updates the Google Toolbar every once in a while…so the PR that the Toolbar is currently showing may not necessarily be what the site’s PR actually is at the moment….but it will give you a good approximation of how well you’re doing.

You can use the Google Toolbar to find out the PR of your site, or virtually any other site as well. That’s good to know. It’s nice to be able to see what your competitor’s PR is!

Take another quick look at that picture above….notice that blue circle with the letter “i” inside it….right next to the PR meter…that’s pretty important too. If you click on it, a small menu will pop up. One of the things on the menu is “backward links”.

That will show you all the other pages that are currently linking to the site that you’re currently looking at. That’s pretty important! Since your PR is based on how many other sites are linking to you, it’s a good thing to be able to tell exactly what sites ARE linking to you…(or what sites are linking to your competitor that gives them such a good PR).

I think it shows the sites that are linking to your site that (themselves) have at least a PR or 3 or higher. Good to know.