Last week I wrote about the importance of flat website architecture and how cross linking can help to improve the ranking of sub pages on your website. This week I’d like to cover this in a little more detail by discussing the concept of PageRank leakage and how you can prevent this happening on your website.
What is PageRank Leakage?
To explain PageRank leakage, you must first understand how PageRank or ‘link juice’ is distributed between various links on a page. Taking a very simplistic view, lets say that a page has 20 ‘PageRank points’ and passes 100% of its link power to 5 other pages. Each sub page would then receive 4 ‘PageRank points’ as shown in the example below:
Keeping this example in mind, let’s say that your homepage now has 5 additional external links to other webpages. Using the formula above, each link now only carries 2 ‘PageRank points’ with half of your link juice being distributed to other external webpages.
PageRank leakage is when outbound links to external websites give away PageRank that could be better distributed among pages within the website.
Preventing PageRank Leakage
The most effective way to prevent PageRank leakage is to eliminate redundant external links. By doing this you will focus PageRank distribution amongst other pages on your website and improve their overall ranking in search results.
Here are some common sources of external pagerank leakage:
- Footer links – this may contain links to the company who designed your website or the website template you are using
- Blogroll links – your blog may contain many external blogroll links
- Advertising links – links to other advertisers can also be a source of PageRank leakage.
Why “Nofollow” Tags Won’t Work
Some webmasters have suggested adding a rel=”nofollow” attribute to each external link to prevent this link from passing any PageRank and effectively funnelling all link juice internally. Unfortunatley, this will not have any real impact as the PageRank for each nofollow link is evaporated, reducing the amount of link juice that can be passed to other pages.