Tom Schmitz // Jun 11 2009
On June 2, 2009 Google reversed itself when it announced that the nofollow attribute (rel=”nofollow”) can no longer be used to redirect PageRank. Google’s Matt Cutts stated that nofollow tags would now evaporate PageRank. This is a major policy change by Google’s, one that impact advanced search engine optimization.
I want to discuss
PageRank,called link juice by some, is a signal created by and measured by search engine results ranking algorithms. This is the foundation of Google’s original rankings algorithm and one of the three pillars of SEO (content, site architecture and links). In simple terms, every link is a vote. A link (vote) from a page that itself has lots of links or has links from highly trusted pages possesses more influence than a link (vote) from a page with only a few links or links from low-authority pages. PageRank can come from internal and external links.
PageRank is reusable. PageRank does not disappear after a search engine weighs a page’s authority. Instead, the receiving page passes much of its PageRank onto the pages that it links to. It passes 1/n of the PageRank to each document the page links to, n being is the number of document being linked to. Because of this nature, we can control the flow of PageRank to boost important pages and promote the indexing of deep content by search engines.
Google and other search engines prefer it when websites do not pass authority to other websites if
1. The link is a paid advertisement or insertion
2. The author or website administrators are unsure about the quality of a web page being linked to
Telling webmasters to not create these links would be unacceptable requirement. Yet, these types of links pollute the search engines’ ranking algorithms. As a band-aid, the search engines created the nofollow tag to keep links in place, but without passing PageRank.
This is how a nofollow tag is placed into a link’s HTML markup:
<a rel=”nofollow” href=”http://www.examplecompanysite.com” target=”_blank”>Anchor Text</a>
PageRank sculpting is an advanced SEO technique used by 3% of web sites. Google web spam team member Matt Cutts has confirmed that, “…you are allowed to control how the PageRank flows around within your site,” and, “…if you have a certain amount of budget of PageRank, you certainly can sculpt your PageRank.” Advanced websites did exactly that.
In large part, PageRank determines how often Google crawls your web site, how many pages it crawls and how many pages it indexes. Every document has a limited amount of PageRank that it can pass. As PageRank is repeatedly passed from page to page it diminishes. Eventually, without external backlinks to refill the tank, PageRank runs out.
Because PageRank is a scarce resource, what you link to becomes important. Even Google’s Matt Cutts suggests that web designers use internal link architecture strategically. For example, from the home page you should link to product pages with good ROI and not to pages that do not sell well.
Many sites do not adhere to a search engine friendly internal link architecture. Instead, designers want to design for people. They frequently use drop-down menus, spider menus or on-page menus to link to every possible category, sub-category and content page believing that this will create a better user experience for their human visitors.
Did you know that a designer’s desire to make every important page immediately available to readers can be counter to people’s normal scan-click-refine web browsing behavior?
To counter this tangle of links, SEO strategists will nofollow links that do not adhere to good architecture to stop them from wasting PageRank.
Google allows webmasters to choose which links pass PageRank and which do not. The most common method for controlling PageRank flow–also known as sculpting PageRank and Link Juice irrigation–was to use nofollow tags like irrigation gates. When the tag is present the gate is closed causing more PageRank to flow through those links with no nofollow tags.
At this month’s SMX Advanced conference, Matt Cutts stated, then later confirmed that using the nofollow tag will not conserve and redirect PageRank. Instead it “evaporates” PageRank. The authority disappears.
This is important because
The best option for controlling the flow of PageRank is to employ good web page and internal link architecture. Here is one example.
The more trust and authority your site has, or the more PageRank you have, the more liberal you can be with your internal linking.
As far as we know it is still permissible to control the flow of PageRank and this can be accomplished by some of the same methods which were popular before the introduction of the nofollow tag. For example, links can be placed in iFrames. An iFrame is web page or web markup snippet that one can insert into a web page. When you disallow an iFrame file in robots.txt its links pass no PageRank.
As for combating the dilution of PageRank in user-generated content like blog comments, we recommend a wait and see approach. Frequent comments are a signal of quality and search engines will not want to punish content that receives lots of comments. Otherwise, sites like TechCrunch would lose their rankings. Expect an announcement from Google to clarify this.
Image by Neil Cummings