Dave, maybe you can explain something for me: my Web site Freedom For Animals.org apparently has a PageRank of two out of ten (2/10), and I don't really understand what that means. Does it mean, for example, that my organization's site is #2 out of 10 hits?

It's hard to pin down exactly what Google means when it talks about PageRank, but the best definition is that its a rough indication of the popularity of a Web page. A higher PageRank indicates a more popular page.

Notice here that I'm not talking about Web sites here too: Google considers every page of a Web site to be an autonomous entity, one thing that quite frequently confuses people. We've all been taught to think about Web sites, but the new, modern Web is all about separate autonomous pages, not sites at all.

Let's jump back to PageRank for a moment, though. Google PageRank is a measure of the relative popularity of a site, ranging from a rank of zero (you have insufficient inbound links or are too new to have a rank) to a rank of ten (which means you're one of the dozen top sites on the entire network).

A few example values: www.yahoo.com has a PageRank of 9, www.google.com has a PageRank of 10, www.microsoft.com has a PageRank of 9 and www.redcross.org has a PageRank of 8.

But PageRank isn't just an indication of how many Web pages point to your page, it's an indication of how important those sites that point to your page are too. This is the piece of the Google algorithm that make its search engine so darn interesting: if a small number of highly popular (e.g., high PageRank) pages point to your page, you could be considered more important than if hundreds of less important Web sites have links to you.

As a result, everyone who pays attention to PageRank dreams of showing up on the Google home page. That'd be a glorious day for your PageRank!

So now that we've talked about how PageRank is calculated, let's spend some time talking about why you should - or, perhaps, shouldn't - care about its value.

First off, let's set aside a common misunderstanding: a higher PageRank does not mean you'll have better Search Engine Results Placement (or SERP, as search engine geeks call it). Or, at least, it's only one of what's likely over 100 different variables fed into the calculation of what Web pages should be shown in what order as the result of a specific Web search query.

You can see that if you've installed the Google Toolbar, actually. Perform a search for something relatively uncommon, then check the PageRank value of the top 10-15 results. You'll see that the top match or two are often not the highest PageRank pages on that list of the top dozen.

In the Search Engine Optimization (SEO) community, a lot of people pay a lot of attention to PageRank, and seek links to their pages (and sites overall) from other sites with relatively high PageRank. Other SEO people, however, encourage all of us to just simply ignore PageRank entirely and instead focus on building good Web sites.

What's my view? Well, as I wrote at length in my popular book Growing Your Business with Google, I think it's useful to pay attention to your Google PageRank, but the best long-term Web strategy is to build a smart site that offers your online community or marketplace valuable content presented in a readable and credible manner.

And, yeah, asking your friends and colleagues for links to your site doesn't hurt either!

This Q&A originally appeared at Ask Dave Taylor.