Why Links Matter?

Whenever I'm asked about what I do for a living, I say something like this: "you know those pieces of text that you can click on inside of a webpage, the ones that take you somewhere else? I place those."
Blank stare. Sometimes they respond with, "OK, but why?" That's a damn good question. The "why" behind the existence of links has been a bit more absent than it should be, especially for people who are new to the field.

Why Do Links Matter?

Hyperlinks were the main method of building the Internet and connecting sites through HTML, allowing people and bots to move around and find what they needed. They were like any other citations, methods of getting additional information by going somewhere else.

Contrary to popular belief, Al Gore didn't invent the hyperlink. The term itself was first used in the 1960s, before most of you were born.

In 1998 there was the first on-paper mention of PageRank, just before Larry Page and Sergei Brin actually founded Google. The theory behind PageRank became part of the basis of the Google algorithm, and continues to be so today.

To greatly simplify the concept, PageRank is a popularity contest wherein the pages with the most support (via inbound links) behind them should be viewed as the most important ones. You could increase a page's importance simply by building as many links as possible to it.

As anyone who deals with SEO knows though, it's a lot trickier than that.

Not All Links Are of Equal Importance

A link from the homepage of a powerful site like the BBC will be of a higher quality than a link from the links page of your high school's blog.

If a competitor that ranked above you in the SERPs had 100 more links than you, you couldn't just go grab 101 links and rank above him. Some links are simply more valuable than others, particularly links from authoritative sites (like respected news sites) and links from .edu and .gov domains.

Like every other SEO tactic, this was abused, differing opinions abounded, and everyone tried to nail down the exact science of it.

In 2005, the nofollow link attribute came along and ruined all our fun. No longer could we throw tons of links at sites in order to make them rank. That can still work as you'll see at times, but quick wins with links aren't as plentiful as they were pre-nofollow.

In 2009, PageRank was removed from Google's Webmaster Tools, mainly due to the fact that people didn't really understand that the number they saw wasn't a true representation of their sites's importance (and was updated about as frequently as your grandma's hairstyle.)

Note: there have been some updates to the original PageRank patent, which Bill Slawski covers in detail here.

The PrePageRank World

What did we do before we had that pesky little toolbar indicator? Without that one commonly misunderstood metric to constantly monitor and agonize about, we used rankings and traffic as an indicator of our performance.

We could also rank a site without links, just by keyword stuffing (cramming keywords into my tags and content to the extent that 50 percent of my words were that exact keyword, for example) and cloaking (figuring out how to send search engine spiders to one place where I keyword-stuffed while showing users a nice, pretty page). Those were the good old days when you could get a link on a site and not get cussed out by your client because they wanted all PR 4s and up and you, stupidly, got a link on a new but very relevant and well-trafficked PR 0 site.

We still knew that links were important. They just didn't make us crazy.

Link exchanges were very big. Having a page just devoted to outgoing links was huge. It was a softer, gentler time when link building as we know it today was innocent. The only people that I knew who built links were generalist SEOs, and looking back now, it's easy to see that we did it badly by today's standards.

Actual PageRank

There's a point that gets lost a lot, one that makes it obvious that actual PageRank and visible PageRank are two very different things.

The PageRank that we can see represented in the bar, a number, from a PageRank checker, etc., is updated infrequently and isn't the actual PageRank that Google assigns to your site. The actual PageRank calculation, if shown here, would make all of our heads spin. Let's just say that it's a lot more complicated than a number from 0 to 10.

Toolbar PageRank

This is what you do see (and sometimes confuse with actual PageRank.) Toolbar PageRank is one of many factors in how your site will rank but its importance is way overblown and oversimplified. You will see sites with a Toolbar PageRank of 1 outranking sites with a Toolbar PageRank of 5, due to various other considerations (like social signals, for example.)

PageRank Sculpting and Link Juice

Now here is where things get particularly interesting to me. Pages have their own specific PageRank (both actual and toolbar) and through linking elsewhere, they can send link juice in the same way that they receive it.

If a page has 10 outgoing links on it and none are nofollowed, each page linked to should receive one-tenth of that page's link juice. If five links are nofollowed and five are not, each of those five followed links should receive 20 percent of that page's link juice and the five nofollowed links should receive none of it.

Due to this idea, people began to experiment with manipulation. (Can you imagine SEOs manipulating anything?) We nofollowed certain links that went to other site pages, ones that weren't quite as important as the others but ones that we did link to in the navigation. That seemed OK.

Later, like with almost everything else, it got complicated. I won't bore you with the details here. Suffice it to say it's not a widely recommended practice anymore. Some still do it, some don't, but controlling link juice didn't work as we hoped it would. You'd think we would all learn our lessons but no, no we never do.

So Why Do Links Matter Today?

Oddly enough, they matter for the same reasons that they have always mattered: they send traffic by making connections and yes, they are still a large part of ranking. I don't see that changing any time soon, even though many people (and myself) think that certain other factors like social signals are becoming important.
A good link will send you nice link juice and help to boost your rankings so that you'll get more traffic and hopefully more conversions. A great link will do the same thing but it will send you traffic on its own.

Some links probably do absolutely nothing positive. You can get a link on a high-profile site and no one will ever click on it. You can receive referring traffic from a footer link on the crappiest site you've ever seen. You can get a rankings boost from both of those links. It's like magic.

Then there's the concept of authority. Links from other sites will lend credibility and authority to your site, ideally, through using you as an example. When a site links to you, the anchor text is viewed as an indicator of what your site is about.

Like the rest of this, that is no longer a perfect system. Theoretically, the keywords that a site links to you with should boost your authority for that topic.

If CNN linked to your site with an anchor of "great place to buy a computer" then your site would probably be viewed as an actual great place to buy a computer, and you'd probably rank higher for that phrase than if you'd gotten that link from your mom's local birdwatching site. However, the birdwatching site would still help you rank for a great place to buy a computer, but since it's most likely not as authoritative as CNN, to actually get a noticeable rankings boost, you'd need to get that link and more of the same for it to make a difference.

CNN has authority signals, which engines can take into account: people link to it, they reference it on Twitter and Facebook, they comment on stories, they comment on videos, the traffic is probably truly amazing, and the brand itself is one that most people recognize. One link from a site like that is much, much more powerful than more links from sites that have no social traction or online footprint.

Here is What I Truly Believe

The importance of links may lessen a bit, but it won't go away completely. The web was built on links. You can rank well without them of course (think breaking news stories or blog posts that get loads of attention on the first few days), but depending upon what shows up in a search engine's results is just as bad an idea as depending upon any one route into your site.

Source: http://searchenginewatch.com/article/2166568/Why-Links-Matter

Introduction to Google PageRank: Myths & Facts

Google's PageRank algorithm has been around since, well, as long as Google itself. Yet there still seems to be a lot of confusion about what it is, how it works, how important it is and how we can use data based on it.

While all of those things have changed to a degree over the years, as Google as refined and developed the way it does things, the basic facts have remained constant.
Before we begin diving into PageRank, however, we need to make an important distinction between two things:

• PageRank: This refers both to the algorithm itself and the score given to each page as a result of it.
  
• Toolbar PageRank: This unofficial term is the name usually given to the publicly displayed PageRank score. Officially, it's only available through the Google Toolbar (hence the name), but in reality many SEO tools provide it.

We'll look at these two things separately.

PageRank: What is it, Exactly?
PageRank is what made Google what it is today: a heuristic analysis of the web's link graph, or, in simpler terms, a concrete, mathematical way to ascribe importance to a web page based on the links that point to it from other web pages.

This is what initially made Google's results so successful compared to the nine other search engines that had come before it. Although they weren't the first to look at links, they were the first to do it in such a meaningful way.

I won't go into great detail on exactly how it works, but if you're interested, Matt Cutts has a decent bit of information about it as the intro to his post about why PageRank sculpting no longer works.

The algorithm itself is described in Brin and Page's seminal paper, "Anatomy of a Large-Scale Hypertextual Search Engine." In other words, it's public knowledge.

However, it is also clear that PageRank has evolved a lot over the last 10 years. The basic structure is probably pretty much the same as it has ever been, but it has become much more sophisticated in many respects (for example, introducing an additional factor for detecting and valuing links based on where they are on a page, as well as on the strength of the page).

For this reason, PageRank as presented in the original paper is usually referred to as pure or classic PageRank, as opposed to its modern counterpart.

It's also clear that Google now uses many other factors to produce the search results that you see every day. Some of them, as with PageRank, will be based solely on links. Others will be based on all sorts of other factors.

Google doesn't reveal how important PageRank is as a part of this total mix, but while its importance has clearly diminished over time, it is still an important part of the total ranking algorithm.

But now that we've discussed the PageRank algorithm itself, what about the number that is derived from it?

Google is also suitably vague about this (and, remember, they don't reveal it either: they only reveal the Toolbar PageRank), but, in essence, it is a logarithmic scale (like the Richter scale for measuring earthquakes) with a base of about 16.

So, that means that a PageRank of 2 is 16 times bigger than a PageRank of 1; a PageRank of 3 is 16 times better than a PageRank of 2, and so on. Just to give you an idea of some scales here:

• PageRank 4 is 4,096 times better than PageRank 1
• PageRank 5 is 65,536 times better than PageRank 1
• PageRank 5.1 86,475 times better than PageRank 1
• PageRank 7 is 4,294,967,296 (over 4 billion) times better than PageRank 1

So, hidden within that deceptively simple scale from zero to 10 is actually a massive range of importance. And this brings us nicely onto Toolbar PageRank.

Is Toolbar PageRank Just the Number From the PageRank Algorithm?
No. Google would like you to believe that this is the case, but most SEO professionals believe that there are other ranking factors from different algorithms mixed in with this number.

However, the main problem isn't whether it is or isn't just PageRank, but the fact that there is precious little information about whether it is or isn't. There are also a number of other problems with it:

1. It's only reported to one significant figure. It should be obvious from the above numerical examples that even the difference between PageRanks 5 and 5.01 is far bigger than the difference between PageRanks 4 and 5. So, the single figure that we're given bears remarkably little information.
   
2. Even ignoring that is it/isn't it PageRank debate, the number given by Google is probably not an accurate reflection of a page's PageRank anyway.
   
3. It's only updated for each page three or fours times per year. In contrast, Google's internal representation of a page's PageRank is probably updated almost constantly.

It should be clear by now that although the PageRank algorithm itself is important, Toolbar PageRank is next to useless as an SEO metric. I would recommend not using it at all as a measure of an SEO campaign's performance (what you should be measuring we can discuss another time!).

It does have one worthwhile use, however, which is looking for manual penalties (although even in this context it should be used with caution). If you are monitoring the rank of a page over time and it suddenly drops, that is a good indication that a penalty has been applied.

Likewise, if you're comparing a page's PageRank with its equivalent mozRank (an indepedent figure that guesses at what a page's PageRank really is) and the PageRank is markedly lower than the mozRank, that may also indicate a manual penalty. This can be useful when selecting link building partners.

It can also have some use for analyzing how Google perceives the importance of pages within a single site by comparing PageRanks across the domain and for looking for missed opportunities (i.e., if you have a page with a high PageRank but no traffic, it probably means that you need to work on incoming anchor text and on-page optimization for your chosen keywords). However, I wouldn't recommend using it to compare page across different domains.

Busting Some Myths
And lastly, lets finish off by dispelling some common myths and misconceptions around PageRank:

1. PageRank acts like a vote for one page by another. It's a great description for lay people, but it really doesn't work that way -- and is actually quite misleading. If you are, or want to be, an SEO professional, it's really worth understanding PageRank properly: read Matt Cutt's post that I linked above (or read the original paper). A good analogy would be that is calculates the probability that a web surfer will end up on any given page if he or she follows links around the web at random. One immediate impact from this is that linking out actually reduces a page's PageRank. It also shows us that a link from a page with many incoming links is better from a page that has just a few.
   
2. Sites have PageRank. No, they don't! PageRank applies just to individual pages, not to sites as a whole. People often refer to the PageRank of their site, but what they are actually referring to (unwittingly or otherwise) is the PageRank of their site's home page. It is thought that Google does have another link based algorithm, often referred to as DomainRank, that works in exactly the same way as PageRank, but at the domain level, not the page level. But that's a different story. It's also worth noting that home pages tend to have higher PageRanks than pages within a site, as they tend to have more links pointing to them.
   
3. PageRank relates directly to traffic. It doesn't. PageRank is an indicator of a page's latent ability to rank, but says nothing about how it is actually ranking or for what terms it is ranking. Think of it as a potential. For actual rankings to occur, Google also has to associate a given page with one or more keywords, however strongly, and it uses entirely different algorithms to do that (both link based and otherwise). So, it is not uncommon to see, for example, a PageRank 3 page getting orders of magnitude more traffic than a PageRank 5 page, because the former is strongly associated with some popular keywords, and the latter is potentially not strongly associated with anything. However, it's reasonable to assume that between two pages equally associated with the same keywords, the one with the stronger PageRank would rank higher in the results (although all the usual caveats in the information given above still apply).
   
4. PageRank shows how important Google thinks your site is. No. PageRank is just one of many factors that Google employs for indexing sites and ranking them.
   
5. PageRank is Google's only link-related algorithm. Again, false -- although when Google first started this was probably true. They now use calculations based on links for all sorts of other things to do with indexation, ranking, and keyword association.

Summary
Having at least a decent working knowledge of PageRank is vital to the working SEO, both in terms of helping with link building and understanding the distribution of PageRank scores around the web. However, as an SEO metric, outside of some very narrow circumstances, Toolbar PageRank is almost completely worthless and should be approached with extreme caution.

Source: http://searchenginewatch.com/3642190