Copyright 2005 SharewarePromotions LtdOne of
most fascinating aspects of web is its dynamism. We all know that it develops at an astonishing speed - yesterday's craze is today's old news, and bigger and better things seem to be springing up every few days. Some of them crumble quickly into dust, while others seem destined to tower above rest.
Naturally, search engines also follow this pattern. Some of early search engine giants remain with us today, but many of them are gone - and every so often, a new champion seems to emerge. Recent years have seen growth and development of a search engine that puts all others to shame. It might have once stood at same level as its rivals, but there is no doubt that for now at least, Google rules web.
Many of companies we work with see more traffic from Google than all other search engines put together, and there are more than a few Search Engine Optimisation services who focus almost exclusively on this one engine.
What is Google's secret?
So why is Google so successful? The answer is simply that when a user goes searching on Google, they're likely to find what they're looking for, and more quickly than on any other search engine. Exactly how Google manages to do this is trickier to answer, as they tend to guard their secrets well. They don't want us to know too much about how they determine their search results, simply because they don't want anyone to be able to manipulate their own ranking.
Of course, human nature dictates that many of us aren't satisfied with this. We desperately want to be able to affect ranking of our sites, and some of us will go to great lengths to do so. We work hard to find perfect keywords, tweak our meta tags and optimise content of our site to what we hope is Google perfection.
But recently, a new word has entered our vocabulary, and is surrounded by so much hype that very few people actually have a realistic understanding of what it is - or what it isn't. PageRank is where attention is focused today, and many companies are determined to find a means of improving their magic number. "I want to be an eight," they say, as if PageRank was a dress size that they could grow into with help of some heavy-duty calorie shots. Unfortunately, it's not quite as easy as that.
So what exactly is PageRank? There's a surprisingly simple answer: it is Google's way of estimating how important a web page is. On a basic level, Google decides that if one page links to another, second page must be considered important. If one page on one site has 15,000 pages linking to it, it must be for a good reason, right?
Page Rank is about pages, not websites
Let's begin by straightening out a few basic points. First of all, PageRank is assigned on a page-by-page basis. A whole website does not have this score, and different pages within a site can have very different PageRank values assigned. Another important point is that rating (out of ten) assigned is essentially little more than an approximation of a given page's PageRank. The actual values cover a far greater range than zero to ten.
Before going any further, we should take a look at most important point of all, often overlooked when we get caught up in PageRank frenzy. PageRank is only one factor that Google takes into account when displaying results of a search. There are still other factors of equal significance in performing well on Google - so don't make mistake of thinking that you would live happily ever after if your PageRank was a little bit higher. Other factors include a page's title, and use of keywords within page's text - not in keyword meta tag.
PageRank is still one of Google's more ingenious strategies, and is certainly one of many reasons that it stands head and shoulders above rest. Partly, this is due to a combination of two factors. Firstly that very nature of PageRank is difficult (but not impossible) to manipulate, and secondly that exact details of how value is assigned is a closely guarded secret.
However, there is one very useful source of data - an academic paper detailing formula used to calculate PageRank from Google's early beginnings as a university project. This formula will have certainly been altered and expanded over years, but it is generally accepted that it still represents essence of their PageRank system
The Page Rank Formula
The exact details are lengthy, and far beyond what I am capable of dissecting. But basic formula is as follows:
PR(A) = (1-d) + d (PR(T1)/C(T1) + ….. + PR (Tn)/C(Tn))
PR(A) is PageRank of a particular page (A) - not a website as a whole.
1-d is dampening factor, as explained below.
PR(T1) is PageRank of page that links to our (A) page, and C(T1) is number of links contained on that same page.
The formula is repeated throughout every single page that contains a link to this (A) page.
Two important points to take into account. First of all, if you're thinking that formula would in practice be an infinite loop, then you're correct. This is very nature of web itself, and is also why Google has introduced so called dampening factor.
The second point concerns way that PageRank is awarded by one page to another. The generally accepted means of understanding this is to consider that a given page has, according to its own PageRank, a certain amount of voting power. If page in question links to five other pages, then each of pages being linked to receive their PageRank "award" of one fifth of original page's voting power. It's also worth noting that number of links on a page includes a website's internal links.
Link farms don't work
This makes it quite obvious that so-called link farms, where each page of a website contains many hundreds of links in an attempt to artificially boost so called "link popularity", are doomed to fail from start. In addition to this, Google has its own system for not only minimising effect that these sites have, but eliminating it altogether. As formula shows, PageRank works as a multiplier of a site's overall value, so Google has made sure that link farms have their own value of zero - which means that a link from them counts for nothing, quite literally.
