A nofollow link looks and works the same as any other link, the difference is that it's an instruction to search engines to 'not follow' the link, i.e. to not give the site you're linking to any benefit as a consequence of your link. It has implications for SEO both whether you're adding an outgoing link to your site or receiving an incoming link from somewhere else.
There are 2 ways to add nofollow to a link:
All links on a page
To add nofollow to every link on a page, then in the <head> section of your code, put the following line:
<meta name="robots" content="nofollow" />
One specific link
In the <a> tag add rel="nofollow".
For example, you might use the following code:
<a href="http://www.example.com/" rel="nofollow">Click here</a>
This code creates the following link:
To see if a web page has any nofollow links, View Source to see the source code, then press Ctrl + F to open a Find window and enter 'nofollow'. If it doesn't show nofollow on the page, all the links are dofollow (this is the default).
How do I view the source code?
The command to view the source code depends on the browser you're using, as follows:
- PC in Firefox, Chrome or Opera - press CTRL + U
- Mac in Safari or Chrome - press Option + Command + U
- Mac in Firefox - press Command + U
When to use nofollow links
Nofollow links should be used in the following situations:
- To show that the link is sponsored or paid for in some way.
- If you're not sure of how reputable or trustworthy the site you're linking to is.
- If you want to make links to a specific page on your site less important (personally I'd avoid this one, as there are better ways to handle this).
- On any links on your site that other people add without you carefully reviewing them first.
In the last of these situations, some examples might include:
- If you have a forum on your site .
- If you allow comments on blog posts or other content.
- On user reviews.
- If individuals can create their own user profiles on your site.
In all the above situations we would recommend automatically adding rel="nofollow" to every external link, as well as configuring a captcha so visitors have to prove their human when posting comments, etc.
Allowing a lot of bad comments on your site will still negatively affect your SEO, however nofollowing the inevitable spammy links that you will get if you allow anyone to post anything on your site, will limit the damage. Google's guidelines also specify that paid links or advertising should always include a nofollow link and if you don't respect this guideline, then Google may penalize your site, therefore all the above guidelines are important for SEO.
Can nofollow links help with SEO?
If you have lots of links to your site and all of them are dofollow, then this may be considered as a suspicious sign. Most social media sites, including Facebook and Twitter also add nofollow to all outgoing links, however Google has an algorithm that takes social media signals into account, therefore these links will still benefit your site.
SEO is also a means to an end and the end goal is gain more traffic to your site and generate sales. Having an interesting blog article on a major news portal, or a video on a popular, related website, for example, will still draw traffic to your site, therefore these links can be very useful, even if search engines ignore them.
When looking at SEO it's always worth taking the long-term perspective into account and if you attract visitors to your site and your site has quality content worth linking to, it's also likely that some of the visitors to your site will in turn link to it, like or share your blog posts, etc.
So the short answer is yes, nofollow links still help your SEO, provided that it's somewhere people will see it and click it.
Google do their best to show the best search results to their clients, therefore if a link is dofollow, but on a low quality, spammy website, it won't help with your SEO anywhere, therefore you should focus on getting as many high quality, relevant, dofollow links to your site, but a nofollow link from a high quality, relevant site is far better than a dofollow link from a spam site.