It is well established that Google Page Rank, or the link juice, doesn’t pass through links with the nofollow HTML tag, and that links with this attribute have no real role to play in the passing SEO strength from one domain to another. However, impact of nofollow links against their dofollow counterparts still remains controversial, and both webmasters and Google are somehow actively debating on this front. Google cleared the air by declaring that nofollow links have no real affect on their search algorithm and the Google Spider Bot completely ignores them during a face off. Many webmasters argue that under certain circumstances nofollow links will negatively affect search rankings if they appear in a bad (or spammy) link network, which Google is constantly on the lookout.
A look at nofollow/dofollow terminology – What means what?
How to identify
<a href=”http://www.website.com/” rel=”nofollow”>Link Text</a>
<a href=”http://www.website.com/>Link Text</a>
Message to the Google Spider Bot
Don’t count this link. Ignore it as it is not important.
Count and index this link. It is important and calculates Page Rank flow.
Page Rank Flow
No linkjuice is transferred.
Linkjuice is transferred.
Spam index rating
Controversial – bad nofollow links could negatively affect search rankings. Not proved, as of yet.
Depends on the quality and type of link. Dofollow from poor website is bad, while it is enviable from a reputed and trusted website.
Debatable – Empirical data suggests in some circumstances nofollow links could become dangerous. Google penalty is hypothetically possible.
Unnatural link structure with over-optimized dofollow links attracts Google penalty. That’s a well established fact and recovery is tedious.
Calculation of Google Page Rank
Every inbound link linking to your website is crawled and indexed by Google to check if any PR is to be flowed from the referring domain to target domain or not. PR is nothing but a quantifiable term that directly affects ranking position of a web page on the search engine result pages (SERPs). PR is transferred to your website when another site points to it through a hyperlink based anchor text, which is measure by Google to determine search rankings. The higher the PR of a webpage, the higher is the webpage’s trust and quality in the eyes of Google. It must be noted that PR depends as a result of a logarithmic function that takes in the number of backlinks inbound and outbound from a referring domain pointing to a certain webpage. Higher the number of linking domains with high PR means higher the PR of the target webpage!
Dofollow links indicate Google that the PR, so calculated as per the backlink structure of a referring domain, must be transferred to the target website or a webpage. This is the fundamental aspect of how Google’s search results algorithm operates and ranks websites based on a certain keyword. When Google’s crawler, aka spider bot, crawls a page and finds links pointing to another website with “rel=nofollow” tag, it interprets that that nofollow link isn’t to be counted in its PR calculation, such that no PR or the linkjuice is transferred between the two websites.
Why the debate?
As per the Google Webmaster Tool, sometimes both dofollow and nofollow links can get nasty with your rankings, especially when they originate in big number from a low quality spammy link network. Further, it is also believed that when the Google spider bot crawls a nofollow link that hasn’t been used anywhere else, and then it will consider it as a dofollow link. There has been a lot of disagreement between webmasters regarding the quality of a backlink that matters the most.
According to Gianluca Fiorelli, “search engines do not carry PR through the no followed link to your site, they record it and they take notice that your site has been cited in a site. If that site is an authoritative one or a trusted seed, somehow its aura will reflect on your own web site, which will gain trust and relevance to the eyes of the search engines, therefore better rankings.”
Role of Nofollow in link structure detox
Nofollow backlinks are usually absolved from link detoxification process, and dofollow links are usually the first priority while cleaning (removing) low quality backlinks. However, nofollow links can under special situations still be harmful towards search engine rankings and could perhaps also result in manual penalties, since Google usually on the hunt for similar spammy tactics. Many of our clients have reported that that their penalty was only lifted after they identified and removed a huge number of nofollow links originating from shady websites. This is what made me realize that that in special cases Google will penalize websites having unnatural nofollow links.
Things to note here
1. Stop ignoring nofollow links and consider them dangerous.
2. Identify bad nofollow link clusters that might attract Google’s attention and eventually a penalty.
3. Monitor your nofollow link structure and take necessary actions if there are any discrepancies.