PageRank Leakage

If you've read PageRank Uncovered or PageRank Explained, you'll probably recognise the effect that I'm going to talk about in this article. It's an effect that I didn't put the name to, but one that I want to cover in more detail here. Why? Because it has become the focus of much attention and confusion lately. Some say it doesn't exist, some say it's a myth. So it's time to explain - can PageRank leak? And if it can, how important is that? The Case against The case against PageRank leaking goes that a page has a certain PageRank. That PageRank determines in part what the pages it links to get as their PageRank. But in doing that, the page itself doesn't actually lose any of it's PageRanks. To put it another way, if Page A has a certain PR, then regardless of how many pages it links to the PR of Page A isn't altered because it links. The Explanation The argument against is flawless with one exception, it ignores the fact that something is likely to link to Page A, that we're talking about a site so the PageRank likely to cycle back to Page A is probably not insignificant. Even though PageRank operates on a page and not a site basis, it is occassionally conceptually better to think in site terms. A site being a system of pages. The unique characteristic of a site is that the pages tend to be tightly linked. This tight linking means that a page benefits itself by linking to pages on the site it's on. Conversely, it does not get the benefit that it would otherwise get if it linked off-site. i.e. PageRank leakage is not a direct effect, but an indirect effect. Those that state that PageRank leakage does not exist are over-simplifying their conceptual understanding. An analogy Consider I have some magic money. $1000 of magic money. You can have that magic money, but there's some rules. The rules are that you have to give it all away. You have to give it to five members of your family and two strangers. There's another rule though, the people who receive the money each have to give 50 percent of what they receive to either you or one of the other six. The final rule is you can divide that $1000 dollars any way you please, giving however much you like (including nothing) to each person. In terms of magic money, how wealthy is your family at the beginning? It has $1000. By human nature, you're going to want to do two things: the first is ensure you get the most money possible and the second is to try to ensure that that money which you can't get goes to your family. So when you first distribute the magic money you're not going to give any to the strangers. You're also going to distribute the most money to the family member who's most likely to give the 50% back to you whilst giving the others enough for them to not get jealous. If, at any stage, someone gives magic money to the strangers then you haven't actually lost anything (I created this magic money out of thin air for you) but you also haven't made the most of the opportunity I have given you. It's that wasted opportunity that is the leak, causing you to have less than you could have had. In comparison to web pages, the other pages on a site are like the family. They are more likely to give back and they are what you are more likely to want a page to give to if it can't have it for itself. Off-site pages are more likely to give to their site's pages (family) than back to you or yours. Categorically PageRank leakage does exist, but it's a logical and not direct effect. It really is another way of saying: "having lower PageRank than you could have had". How Important is PageRank Leakage The big question then becomes, should you not link out for fear of PageRank leakage? The answer of course depends on how much you need PageRank, how competitive an area you are in and whether you can target that PageRank to the right pages. To know that, it's probably best to read PageRank Uncovered. However, what we can say here is that even in the most competitive areas it is normally the case that some pages on a site need PageRank to rank and others do not need as much. It is also normally the case that people have not first tried to distribute the PageRank well before they worry about losing any. The spending effect When you link out from your site, there are benefits to doing so. Both in terms of user experience and in terms of ranking. The negative side is PageRank leakage. In this respect I would rather call it PageRank payment. This really breaks down to a very simple equation: You should always link out to a site if it brings you more benefit than the PageRank you would lose. That, like any purchasing decision is a judgement call that is up to you and doesn't necessarily need a value putting on PageRank for you to make it. The other point to make here is that if I want to buy a coat, and I can buy it in one shop for $50 or another for $75. I'm going to buy the $50 version. Which simply means, do all in your power to minimize PageRank leakage but do not be afraid to spend PageRank when the benefits seem worthwhile.