Page Rank, referred to SEO (Search Engine Optimization) dudes as PR, is a Google invention which ranks a webpage according to how many other webpages link to it. Before Google came along the web's main search engines were Yahoo and MSN, and a bunch of others.
They all thought they were kings, but a Stanford university student felt that a search engine could generate better results than simply by looking at the number of keywords in a webpage, or how many times certain words repeat themselves. This, after all, can be easily modified so that one can cheat their way to the top of a search engine. This is why, before Google, you might have often found yourself stumbling on porno sites totally unrelated to the search you were interested in.
The principle of Page Rank is that when someone links to your page from theirs, whether their page is another webpage, blog or directory, it is like a vote. A human has looked at your page, thought its content was useful enough to link to, and the more people link to your page, the more convincing it is (to the search engines, for example) that your page is actually useful and not some porno site unrelated to the various keywords which that site might be hacking its way to the top of the search engines in. Furthermore, the words linked out from to reach your page serve as an indication of the page's content being linked to. For example, more often might people link to a webpage on candles using the text, "Hey, check out this great candle website I found," rather than, "Hey, these candles truly light my porno fire!" Therefore, not only do more links to your page increase its page rank, but a reasonable consistency of the words being linked out from will push up that page higher on google in those keywords. Especially if those keywords are similar to the keywords found on your website. [For example, at the beginning of a certain baboon's presidency, his online CV scored number one on google in "absolute failure". This held for a while, but the burning bush complained enough, or used its mighty powers… I'm sure his CV did not contain the words "absolute failure", yet it scored so well. This is because people caught onto this word linkout tool, the word got out in the blog community, and everyone started linking out to his online resume from these keywords (the tactic referred to as a "google bomb"). Google politely declined (I read the official response and it was wittingly humorous) against Whitehouse pressure, arguing that this is democracy, these are legitimate votes, and that google does not manually tamper with or make exceptions like this to its algorithm. Well, eventually it did tamper, for who knows what goes on behind the executive scenes. On a side note, if honesty were to reign, perhaps the CV should have had more frequent reoccurrences of the keywords "absolute failure"?)
This Page Rank concept has been incorporated into google's algorithm (the mathematical formula google uses when calculating how pages should rank in its search results, in certain key words) to make google's search results more accurate and pertinent than the other search engines. It took a while for the others to catch on, and they certainly did eventually start incorporating this same tactic, but it seems it took them long enough that, by mere word of mouth, google became the dominant search engine, now used by more than two thirds of internet surfers and giving google healthy revenues of more than 15 billion dollars a year (slowly even catching up to the mighty Microsoft!).
It is precisely this reason why search engine optimization dudes and dudessess the world over have resorted to mad link exchange frenzy. It has become like trading baseball cards: "Okay, I'll link out from X page with a page rank of 2 and from my Y page with page rank of 1, while you link back to me from your Z page of page rank 3". Countless programs have hit the market which search out the web and write automatic emails with words like, "Hey, I really appreciate what great work you've done on your website <automatically insert website here> and looks like we have similar interests. Would you like to link exchange? As you know, google…". Because many of my pages are near the top of google, I'm constantly getting flattered with such automated emails, and you think they were asking me out for a date!
Of course, google's big aim, and a reason for its big success, is to always deliver the most accurate search results, in which case it has caught onto this link exchange frenzy and incorporated into its algorithms some nasty tricks to cancel out these endeavors. A seasoned search engine optimization dude like myself will know what these are and how to circumvent them. One little secret is to "triangulate" your link exchanges. Don't link your X page to my Y page, and I link my Y page directly to your X page. That's just too darn obvious what we're up to, isn't it? Such triangulation works best if working off different domains. These days it's not expensive to buy new domains, like mydomain.com, so now you can link out from mydomain.com/page_X.html to your page Y, and you link out from your page Y to mydomain2.com/page_Z.html, for example. There are many tricks to this game.
In any case, one of the reasons why I wrote this page is because of all those dating type dudes and dudesses who have been courting me with link exchange requests, yet the page they offer to link from to mine has zero or a nonexistent page rank! Not really worth my busy time to manually add links on my high ranking pages to theirs (I have a special, automated one reserved for that). To find out a page's page rank you can install add-ons to your browser, or use a website to do that for you, such as this page rank checker. Notice how this page's page rank is 6 out of a maximum of 10, which is pretty high. Obviously I'm giving it one more vote, and might just nudge it up to a 7 one day. 10 is very very high, and I've only seen a few pages with such an amazingly high page rank. Should we be surprised that the few I stumbled on were google pages??
Benefits of a High Page Rank
One obvious benefit is it should have a positive effect on the page's rankings in certain keywords. For example, with a nonexistent or zero page rank a candle website might be 20th on google for the search term "candle".
But if the site has a page rank of 4, let's say, it might end up in 10th place on google. One can still rank high on google and other search engines with a crappy page rank, but a higher page rank will certainly have a positive affect on the site's rankings in every keyword search.
Usually the main entry page at the top of a domain, such as http://001yourtranslationservice.com/, will have the highest page rank, but I believe it is like Reagan's famous "trickle down theory", or like a tent, whereby the higher the entry domain is, the more positive affect it can have on the rankings of its subsidiary pages, like this one (http://001yourtranslationservice.com/search-engine-optimization/page-rank.html). But that is speculative theory. Then again, search engine optimization dudes and dudesses use a lot of intuition, speculation and experimentation.
Another benefit of high page rank is reputation. For those geeks out there who already know what page rank is and have a suitable add-on installed in their browser, they will look at these websites with greater respect. Need a translation service? If you were such a geek, wouldn't you naturally trust a website which has a higher page rank than some Russian, potentially fly-by-night translation service which doesn't have any page rank? A higher page rank implies that the company (or at least domain - because there also a market for selling high page rank domains if a company goes belly up) has been around longer, and that all those links to it must mean that the service could be pretty darn good and reliable.
And the last benefit I can think of is that you are constantly being courted by the dating crowd who would just love to exchange links with you. The more dudes/esses out there who want to fraternize with you in this way, the more links you'll get to your pages, the higher the page rank you will develop over time, the higher your overall rankings, and hence the more frequent times you will be discovered and thus courted, until you become the most popular kid in highschool!
Speakin of which, wanna go on a page rank link exchange date with me?