Introduction of Google PageRank.
Google PageRank (PR) is a measure of how important a particular web page is compared to other pages online. Web pages are assigned a PageRank score between 0 and 10. A PR0 site is least important and a PR10 site is most important according to Google's reckoning. Webmasters strive to get as high a PageRank as possible. A high PageRank means higher standing in the search engines, increased traffic, increased product sales and brand awareness and personal satisfaction on the part of the webmaster. There is also a high degree of kudos attached to having a high PageRank site. Google are very secretive about the process of assigning PageRank values. One of the key factors they do reveal is that the link structure to and from your site is crucially important. PageRank is not determined by how much traffic your site actually gets, but rather the potential it has to attract future traffic through links. There are many, many reviews that claim to give you the secret of getting a high PageRank quickly ? I am making no such flamboyant claims. What I present in this article is a consolidation of the key points I have found elsewhere.

The PageRank System.
The PageRank system counts a link from one site to another as a vote for that site. The site that has the most inbound links, having given fewest outbound links in return stands highly in this head-to-head system of voting. Another detail that Google reveals is that sites which are them self important (high PageRank) have more weight when voting (linking to) for a site of lesser importance (low PageRank). Google update the PageRank assigned to every website on three or four occasions a year.

The content of the link origin and destination pages is also important. It is advantageous to attract links from web pages with similar content. A link from a PR2 page about holidays to a PR0 page about holidays has more weighting than a link from a PR2 page about pets. The actual anchor text, the text containing the hyperlink, is also very significant. It is desirable to have specific keywords in the anchor text, which relate directly to the content of the destination page.

Content is king. Google indexes pages using an automatic crawler called the Googlebot. Googlebot explores all web pages on a regular basis and can detect which pages are active (eg. regularly updated) and inactive (eg. dormant or rarely updated). Pages which are actively updated are crawled more frequently than those that aren't. A site updated daily can certainly expect to be Googlebot crawled once a week. You can check this out for yourself ? do a Google search on a particular keyword and compare the cached pages of a frequently updated site and a dormant site ? you'll see the active site has been cached, hence crawled by Googlebot, more recently than the inactive site. The fresher your content, the greater its depth, the more likely it is to be thoroughly explored by the crawlers. Original content is better than copied content ? avoid cannibalising Wikipedia to bulk up your pages.

Building PageRank ? Getting Links.
I've already said that the ultimate aim is to have as many inbound links, preferably from relevant high PageRank sites, and as few outbound links as possible. Links to your site can be either reciprocal, where you link back to a site linking to you, or non-reciprocal, where a site links to you but you don't link back to it. It goes without saying that non-reciprocal links give you an advantage in the head-to-head voting stakes, but these are inherently difficult to obtain. The internal link structure of your site is also a consideration ? a good flow of easily navigable pages is preferable to a disorganised mess.

Reciprocal links are worth chasing, but will only be beneficial if you link exchange with a relevant site of equal or higher PageRank. Obtaining reciprocal links is simply done by firing off a polite email to your target link partner. You will have even more influence over your potential link partner if you compliment their site and explain how relevant it is to your own. Better still if you tell them you and have already linked to them - nine times out of ten, if you say you have already linked to someone, they will feel obliged to return the favour and link back to you.

Non-reciprocal links are harder to come by, but a good place to start is the online directories ? specialist directories of high PageRank being the most effective option. Aim for those directories that don't require a reciprocal link. To avoid spammers most directories will require you to register. I recommend starting a new email account specifically for this purpose ? the directories will invariably try and spam you themselves! Entering the same data in the registration forms of many directories can be a very tedious process, but persevere and consider the long term benefit instead of the short term inconvenience.

Forums are a brilliant hunting ground for Googlebot because they have a very high turnover of new content. Capitalise on this by joining a few different forums, posting regularly and appending your link in your signature block. Very shortly you'll have your link on hundreds of different forum pages, multiplied by the number of forums you're involved with.

Buying links is also another option but I'd personally avoid it and look for organic, content-based links every time.

PageRank Summary.
PageRank is a measure of how important your website is compared to others. A high PageRank leads to increased traffic, increased product sales and brand awareness. As a webmaster you should try and increase your PageRank by:

Trying to get non-reciprocal links .
Obtaining links from sites with a similar theme.
Obtaining links from sites with an equal or higher PageRank.
Keeping your site original, fresh and regularly updated.
I hope you've found this article useful. With a little extra effort link building now it really is possible to achieve a reasonable PageRank in the future.