Backlinks is one of the factors that determines rankings of websites. More the backlinks, greater will be the viisbility on search engines. The underlying assumption is that people link only to pages they like. But this is not always true.

If a page A has a backlink to a page B, it doesn’t always mean that page A is endorsing page B. For example, a blogger might have written a bad review about a shopping site, and has also provided a link to it. The bloggers intention is to tell his readers that the shopping site is not a good one. But as he provided a backlink to the shopping site, Google may think that he is recommending that site. To deal with such situations, the concept of do follow and no follow links was introduced.

When we say that a link on site A to site B is do-follow, we mean that site A is endorsing site B. On the other hand, when we say that the link is no-follow, it means that the link shouldn’t be considered as an endorsement. Note that this is different from site A saying that site B isn’t a good one. A no-follow link is seen as a neutral opinion while a do-follow is seen as a positive opinion. There is no concept of negative opinion.

In terms of SEO, a search engine will consider only do follow links when counting the number of backlinks to a site.

HTML Code for no-follow links

Links in webpages are stated using the <a> tag. For example, a link to the homepage of this site in HTML would look like

<a href="http://www.blogarchitects.com">Blog Architects</a>

The result of the above HTML code is

Blog Architects

Links are do-follow by default. So, the above link is a do-follow link.

To make a link no-follow, the <a> tag is modified to include a rel=”nofollow” attribute. The HTML will now look like

<a href=http://www.blogarchitects.com rel="nofollow">Blog Architects</a>

The result of the above HTML code will be

Blog Architects

Note that the final output remains the same whether or not you include the no-follow attribute. However, the search engines will be able to distinguish between the two.

Some people add a rel=”dofollow” attribute to links to tell search engines that the link is do follow.

<a href=http://www.blogarchitects.com rel="dofollow">Blog Architects</a>

There is no concept of a rel=”dofollow” attribute. Links are considered as do follow by default if the rel=”nofollow” attribute is not present.

When to use no follow links?

In negative reviews

If you are giving a negative opinion about some page, then using a no-follow attribute is suggested. This, however, is not compulsory.

In sponsored posts and advertisements

If you are paid by someone to write a post about their site or place an add on your blog, you should make all links to their site on that sponsored post or the ad as no follow. This should be followed by all bloggers as stated in the Google Webmaster Guidelines. If you do not do so, then manual action can be action and your site will be demoted from search results. The reason is that links are the currency in the world of SEO and they can boost a site’s rankings. If someone is paying you to include a do-follow link to their site on your blog, it means that they are trying to game search engines (black hat SEO) and you are taking part in it and hence you are liable to be punished.

Should all external links be made no follow?

Some people recommend that all external links should be made no follow and the reason they cite is that if your page has a link value (PageRank) of 4 and it has 4 links – 2 to external sites and 2 to pages of your own site with all the links marked as do-follow, then each of the four pages gets a link juice of 4/4 = 1. Now, if you make the external links no follow, then the link juice passed to your 2 internal pages will be 4/2=2. The formulae they use is Link Juice = Page Rank / Number of do follow links. This calculation was true in the past but not now.

Now, in the second case, the link juice will still be 1 for the do follow links but 0 for the no follow links. Making external links no-follow will not give you any extra advantage.

However, there might be other reasons why you want to make external links no-follow. Say that you have a competitor to whom you have linked from one of your pages. Both the linked page and the linking page deal with the same topic. The backlink you have given to your competitor will increase the value of his page. In a way, it can be considered as making your page a bit less relatively important from the viewpoint of search engines. In such a case, using no follow links is a good thing to do. Some might say that this is unethical but many sites follow it and it is not a black hat technique.

For example, consider the site stackoverflow.com which is a very popular question and answer site for programmers. Initially, all external links were no follow and during that time, their site performed very well in SERPs. Once, they changed those links in answers to do follow after which the rankings of the linked pages increased and they were shown higher in SERPs than the linking page. In short, making the external competitor links do follow has reduced their rankings. When they changed the links back to no follow, their rankings came back to normal.

 How to find whether a link is do follow or no follow

You can check whether a link is do follow or no follow by looking at the source HTML in your browser. Right click on the link and select ‘Inspect Element’. The Inspector window will open and will show the source code of that page with the HTML code corresponding to that link highlighted. If you find the text rel=”nofollow” in the source HTML, then that link is no-follow, else it is do follow. You can try this method using the following two links. The first is do-follow and the second is no-follow.

Link 1: Blog Architects

Link 2: Blog Architects

find if link is do follow or no follow