How it works
Let’s say a link on your page to another is counted as a ‘vote’, and that Google collects these votes and puts the page with the highest ‘votes’ at the top of page rankings. Unfortunately, this is not strictly how it works (thousands of other factors affect your search rankings) but it gives the page an edge that others might not.
The method works because If you have some useful information on your website, and people quote and link back to it on their own site, then Google will consider it ‘more informative’ than other pages and so bump it up the page rankings.
For example, you have an infographic on your website about ‘The best way to build a website’. I have read it and think it’s worth spreading among the web developer community and so I put a link on my own website saying “Hey, check this out!”, this is going to direct people to it, Google recognises this and thinks “It must be a good Infographic, people are interested, better bump it up the rankings” and that allows your infographic to be found by even more people.
Sometimes, you might want to link to a page but not give it this ‘vote’, you can do so by adding a ‘nofollow’. The ‘nofollow’ is a value given to the Rel attribute of an anchor tag in HTML.
How to use it
Your usual anchor tag will look like this:
But if you want to add a ‘nofollow’ it looks like this:
<a href="http://fifteen.co.uk/" rel="nofollow">Fifteen!</a>
This will allow Google Search Engine Spiders to find the link, understand the nofollow value and then prevent it from giving the linked page a ‘vote’.
If your site is built in WordPress, you can add a ‘nofollow’ by clicking the ‘Text’ view at the top right of your WYSIWYG and inputting the HTML.
When to use it
In WordPress, the most appropriate times to use the ‘nofollow’ tag is to prevent user-generated content e.g. comments, from giving links ‘votes’. It is a common practice for hackers to add comments and link drop within them to build SEO for their own web pages, at the same time damaging your own SEO. By giving these links a ‘nofollow’ you can prevent Google from following through these links and protect your SEO.
Another usage is if you want to link to information or infographics, without giving these pages your ‘vote’, you can use a ‘nofollow’ to stop Search Engine Spiders from clicking these links and prevent them from receiving your endorsement.
***WARNING: It is advisable NOT to do the following***
If you have paid links on your website, they should be set up in a way to prevent them from influencing search results and that any paid relationship is completely disclosed in a way that is user and machine readable. Google advises that any links of this type should include a ‘nofollow‘ tag.
By offering to add backlinks to your website for money, to allow websites to quickly build their SEO is considered a black-hat practice and unethical, and Google will penalise a website that does this. If a Google Spider discovers you are doing this then you will receive a penalty to your SEO. However, should the penalty be granted manually it will be much harsher, and harder to come back from.
To prevent your own website from being penalised, we advise you not to offer paid links, or to buy links from anywhere. You can find out more about how Google handles these kinds of links in Google’s Quality Guidelines.
Backlinking, and when you should use rel=”nofollow”
The “nofollow” was introduced to assist webmasters in protecting their SEO, but there are methods to protect your SEO that go beyond adding an attribute to links on your page.
In WordPress, you can choose to moderate comments on your website, and disallow any comments that you perceive as spam, preventing the links appearing on your website and preventing the need to add the ‘nofollow’ tag.
The ‘nofollow’ attribute is understood differently by different search engines, and adding it to a link does not necessarily mean a search engine will ignore it.
It doesn’t prevent spam, it just sweeps it under a carpet, your website…
If you want to find out more, you can visit the Google Webmaster Tools Help section.