PageRank is what Google uses to determine the importance of a web page. It's one of many factors used to determine which pages appear in search results.
The History of PageRank
PageRank was developed by Google founders Larry Page and Sergey Brin at Stanford. At the time that Page and Brin met, search engines typically linked to pages that had the highest keyword density, which meant people could game the system by repeating the same phrase over and over to attract higher search page results.
PageRank is patented by Stanford, and the name PageRank likely comes from Larry Page.
What Does PageRank Measure?
PageRank measure's a web page's importance.
Page and Brin's theory is that the most important pages on the Internet are the pages with the most links leading to them. PageRank thinks of links as votes, where a page linking to another page is casting a vote.
This makes sense, because people do tend to link to relevant content, and pages with more links to them are usually better resources than pages that nobody links.
PageRank doesn't stop there. It also looks at the importance of the page that contains the link. Pages with higher PageRank have more weight in "voting" with their links than pages with lower PageRank. It also looks at the number of links on the page casting the "vote." Pages with more links have less weight.
This also makes a certain amount of sense. Pages that are important are probably better authorities in leading web surfers to better sources, and pages that have more links are likely to be less discriminating on where they're linking.
How Important Is PageRank?
PageRank is one of many factors that determines where your web page appears in search result ranking, but if all other factors are equal, PageRank can have significant impact on your Google rankings.
Are There Flaws in PageRank?
There are certainly flaws in PageRank. Now that people know the secrets to obtaining a higher PageRank, the data can be manipulated. Google Bombs are a classic example of PageRank manipulation.
"Link farming" is another method people attempt to use manipulate PageRank. Link farming is the practice of linking without thought of the relevance of the pages being linked, and it is often automated. If you've ever run into a web page that was nothing but a collection of random links to other websites, you may have run into a link farm.
Google has adapted their calculations to filter off possible link farms. This is one reason why submitting your website to directories with low or no PageRank may be a bad idea.
If you find your website linked in a link farm, don't panic. In most cases this has no effect at all on your ranking. You can't control who links to you, anyway. Just don't link back to link farms and don't submit your site to them intentionally.
How Can I See PageRank?
PageRank is measured on a scale of one to ten and assigned to individual pages within a website, not the entire website. To find the PageRank of a page, use Google Toolbar. Very few pages have a PageRank of 10, especially as the number of pages on the Internet increases.
How Can I Increase My PageRank?
If you'd like to increase your PageRank, you need to have "back-links," or other people linking to your website. You can trade links with other people, but make sure you only trade relevant links, and make sure you're not trading links with a link farm. You can register your website with directories, such as the Open Directory Project, but use directories with high PageRank whenever possible.
As you build web pages within your website, you can create some of your own back-links by linking to relevant pages within your own website. This is a technique you may notice on this website. However, remember that the number of links you create counts into the equation. Don't overdo it.
The best way to increase your PageRank is to have quality content that other people want to link.