What is PageRank?

PageRank is a ranking system that previously was the foundation of the infamous search engine, Google. When search engines were first developed, they ranked all websites equally and would return results based only on the content and meta tags the pages contained. At the time, however, the PageRank system would revolutionize search engine rankings by including one key factor: a site's authority.
To determine how important, or authoritative, a site was Google chose several big sites, such as cnn.com, dmoz.org, and espn.com. These sites were clear authorities, and Google figured that if these websites chose to link to another site (let's say site B), then site B would receive a piece of that site's authority. If site B were to link to another site (how about C), then site C would also receive a piece of authority, though much smaller.
Using this system of passing authority, Google would then count up how much authority a site had and give it a PageRank from 0 to 10. The PageRank system has become more complicated since then, but this is how it all started.

What's my PageRank?

If you would like to see what PageRank your site has or other sites have, install Google's Toolbar. Google has made a small green bar that starts at 0 page rank (a blank bar) all the way up to 10 (a full green bar, which is 100% authoritative). It should be noted that the PageRank shown in the toolbar is an estimate released by Google, and it is only updated every 3 months or so.

Who Uses PageRank?

When PageRank first came out, only Google was using the technology, but as other search engines have seen how much it improved Google's accuracy, nearly every search engine has added the PageRank system in to be at least part of their algorithm. In the past, while many of the search engines were still working on adding PageRank to their search algorithm, some couldn't wait to make their own and instead signed deals with Google to have them power their results (Yahoo did this for quite some time).
Apart from search engines, SEOs (Search Engine Optimization specialists), link buyers, webmasters, marketers, and anyone interested in a site's value will often look to the Google PageRank when trying to quickly determine the importance of a site.

How Important is PageRank?

When Google was in its childhood, PageRank was the single most important factor for ranking well. However, as soon as the SEO community caught on to this, there was a great deal of people who found ways to artificially boost their clients' PageRank. Those sites became more authoritative than Google thought they should be. Since then, Google and other search engines have constantly refined how important PageRank is, and its importance has definitely declined through the years.
One tactic Google uses is to update Google Toolbar PageRank values four times a year instead of every week, making it difficult for SEOs to know a site's real PageRank. Another tactic is to prevent a site that has been known to sell links from passing any of its PageRank (authority) on to sites that it links to. However, Google can't use that tactic too much because then they run the risk of preventing good sites from being ranked as they should be.
This is a battle between Google and SEOs that will not be ending anytime soon!

Where do I Get PageRank for my Site?

Now we've come to the part where you actually have to do work! It's tough, but getting a high PageRank for your site should definitely be part of your longterm SEO strategy.
The only way to get PageRank is to get a link from a site that already has PageRank. This means that getting a ton of links from PageRank 0 sites will not help your score. However, a single link from a site with a PageRank 6 can immediately boost your site to a PageRank 5 if the site is trusted by Google and is not linking to a massive amount of other sites.
The process of increasing your PageRank is directly tied to link acquisition. Link acquisition is getting links from other sites, be it via natural or through link purchasing. We cover both of these topics in greater detail, and you should read each lesson to learn more about the benefits and drawbacks of each.

Final Thoughts: PageRank

Although not nearly as important as it used to be, PageRank can still be the deciding factor that bumps your site to the top of the search engines. Not only that, but it is also a good indicator of which sites you should spend your most time trying to get links from. Sites with a PageRank 0 are either being punished by Google, or just have an authority of zero, nada, zilch, bupkis, and generally not worth your time.