PageRank is a measure of the importance of any of your pages on the World Wide Web! Or more precisely - it's Google's view of the importance of your page.
How can you see your PageRank?
To see PageRank for any page on your site, or any page that you visit on the web, you'll need the Google Toolbar.
You can download the Google Toolbar for the Internet Explorer and Firefox browsers.
The PageRank feature is part of the toolbar. It's a horizontal white box that may have a little bit of green in it for a PageRank 1 page (not terribly important) or a long green line for a PageRank 10 page (the most important you can get!)
If a page has zero PageRank
this may mean that the page hasn't been indexed yet, and/or the site or page is new
it could be that the page has very few links pointing to it
or it could mean Google thinks the page or site is violating its webmaster guidelines...
...or it might just mean that Google thinks your page isn't important at all - ouch!
How is the importance of my page measured for PageRank?
If you hover your mouse over the PageRank feature of the toolbar, you'll see this little description pop up:
PageRank is Google's measure of the importance of this page (2/10).
So what's important for Google? In a word - links.
"PageRank reflects our view of the importance of web pages by considering more than 500 million variables and 2 billion terms... PageRank also considers the importance of each page that casts a vote, as votes from some pages are considered to have greater value, thus giving the linked page greater value."
In other words, links to pages of your site all count as "votes" for you; Google also analyzes the quality of those pages linking to you.
How can I improve PageRank?
The simple answer would be to start link building - a few good reciprocal links as well as one-way links in.
If your site has useful information, other sites will naturally start linking to you. So one way of getting more links... to help your PageRank to increase... is to provide yet more quality information on your site that other sites will want to link to.
But don't rely just on the "democratic nature of the web" - make an effort to get some good sites to link to you.
All this takes time. Time to build your content-filled website, time to get your links organized - and so for most webmasters, higher PageRank is a bit of a waiting game.
Is PageRank important?
Some people think that PageRank is simply designed to give webmasters something to talk about ;)
PageRank can be useful
if a site with high PageRank links to you - that could help your PageRank
if you link to a great site that happens to have high PageRank - this adds credibility to your site
if you're considering linking to a site but then you see it has no PageRank as mentioned above; if it's not a new site, you might wonder if it is in Google's bad books, in which case you might steer clear of putting such a link on your site.
Generally, PageRank may be seen as a kind of guide; but it's not the be-all-and-end-all.
And it doesn't tell you which sites rank well - you'll find PR3 sites ranked above PR6 sites in the search engine results pages for various keywords - test this out for yourself.
More important than PageRank is your traffic. Does it really matter if you have a PR2 page that gets hundreds of visitors a day? Better than a PR9 page that maybe two or three people glance at.