An Introduction to PR
The complexities of Google's PR (Page Ranking) System have grown more difficult to understand since Hilltop Algorithm was introduced. This beginner's guide to PR system explains basics of what PR is, what it does, and how it affects your site's rankings. This revolutionary search algorithm has made it to where most relevant and popular sites with best content do best on Google's search page. Keep in mind, this algorithm is kept secret by Google for fear of it being exploited, but basics have been released for study.
In a nutshell, Google's Page Ranking is a system devised to rank pages based on their content and popularity and place them accordingly within search results based on their relevance to general topic. Or, in laymen's terms, it's a system to make sure sites are put where they need to be, both in search results and in rankings. A site dealing with pet care is not going to be listed in top 10 when searching for "web design," but depending on its content and popularity it could be well towards top of list on "pet medicine" or "sick dog."
PR is on a scale of 0 to 10, with 10 being highest ranking possible. Of course, only a very few sites have a PR 10 or even a PR 9 for that matter. PR 7 and PR 8 sites are considered very good sites, with lots of original, relevant content and a great deal of inbound links. You will usually find sites with a high PR at top of list under Google's search engine, and many others, since relevant content and lots of links is almost a prerequisite for being placed high in any of major search engines on any of major keywords.
PR is set up to "pass on" from one site to another, or one page to another if it is within your own site. As PR "spreads" throughout your site, you will get less and less utility from it. A link from a PR 5 site to your main page will give you a PR 4 link to your main page. Since your main page will be linked to other pages within your site, any links on your front page (up to 100 pages) will then receive a PR 3 link from your main page. It continues to trickle down, exponentially losing power until it peters out.
Keep in mind, however, that depending on what page linked to you, and how many links were on that page in first place, your PR could be significantly lower than expected. If a PR 5 page links to your site, but has 300 other links on that single page, you may get anywhere from 0 to 4 PR. Thus it is beneficial to have a limited number of links on your main pages, due to smaller amount of PR being passed down with more links it is being passed to. Overall, a small, concise site with lots of inbound links and few outbound links would be ideal "PR trap," although relevant, original content is needed as well.
PR's Effect on Rankings
The effects of PR are plainly viewable to anybody with Google Toolbar. Simply search for a keyword, and look at PR rating of top 10 sites. The highest PR will usually be on top of list, depending on content. If a PR 8, however, has a keyword that does not match their content, they will most likely be ranked lower than a PR 6 on same keyword with more relevant content on subject matter. A site with high, relevant, and original content, along with matching keywords and a multitude of links from related sites, will place extremely high on searches containing their keywords. A site with old content that is not updated often with links from non-related sites and keywords that do not relate directly to their content, on other hand will probably not show up within top 100 sites on same search.
So basically, PR is what drives listings on Google Search Engine. How to optimize your site to take advantage of this system, however is real challenge.
To make proper use of PR system, many different things must be done to assure your website is "acceptable" within their guidelines. Basically, making your site more relevant to your topic will have a great effect on your PR ranking, especially if you are "popular" among those sites, or have many links coming from related sites. Each site on internet has a Page Rank, assigned by Google, based on their content and popularity. To view page rank of each site, download Google Toolbar from their site. It will automatically show you rank of page you're on with a small counter on your task bar.