Ever seen a road sign that says - STOP! Road Blocked!
That's exactly what a Nofollow tag tells Google (Or to be more precise - Googlebot).
When you add NoFollow to a link, you tell google not to crawl (follow) that link.
You also tell Google that "Even though I have added a link to this website, I don't necessarily trust this website. I don't vouch for this website."
Therefore, when Google (or any other search engine) sees a NoFollow link,
- It does not crawl the link. (Here's an experiment proving this)
- It discards the link - does not give it any SEO value.
In other words, a link with a nofollow is worthless from the SEO perspective.
Yes, a human visitor can still click the link and visit your site. But Googlebot (and other search engine bots) won't.
Here's how a nofollow attribute looks like (on a link level):
<a href="http://sitename.com" rel="nofollow">Link Text</a>
Note: NoFollow can be added on a link level (for individual links) and on a page level (all links on a particular page). Will discuss this further in this article.
NoFollow can be applied to both internal and external links
Internal links are links within the same website.
For example, if Website-A links to another page within Website-A, then that's an internal link.
External links are links to other (external) websites.
For example, if Website-A links to Website-B, we can say that Website-A has an External link to Website-B. From Website-B's perspective, we say, Website-B has a Backlink or Inbound link from Website-A.
A NoFollow attribute can be added to both internal as well as external links.
Different ways of adding a NoFollow Tag
Before we learn how to identify a nofollow link, we need to learn the different ways to add a nofollow link.
As mentioned earlier, a NoFollow tag can be added on a link level (for individual links) and on a page link (all links on a page will be nofollowed).
1.) Link Level NoFollow: You can add NoFollow to individual links on a page. For example, a page might have 20 links and out of them 2 links use the NoFollow tag.
Here's how the HTML looks like:
<a href="http://sitename.com" rel="nofollow" >Link Text</a>
For more details visit this link: https://support.google.com/webmasters/answer/96569
2.) Page Level NoFollow: You can add NoFollow to an entire page. In this case, all links on a given page are automatically NoFollowed. If a page has 20 links, all 20 links (both internal and external links) will be NoFollowed.
To add a page level NoFollow, a Robots meta tag needs to be added within the 'head' tags (<head></head>) of that particular page.
The HTML code for the Robots meta tag is follows:
<META NAME="ROBOTS" CONTENT="INDEX, NOFOLLOW">
If a page has this Meta tag within it's head tags, all links on the page will be automatically NoFollowed.
For more details visit this link: http://www.robotstxt.org/meta.html
Is it NoFollow tag or attribute?
To be politically correct, when a NoFollow is applied on a link level it is called a NoFollow Attribute and when a NoFollow is applied on a Page Level it is called the NoFollow tag.
How to check if a link is nofollowed?
You cannot simply look at a link and tell if it is 'Followed' or 'NoFollowed'. You will either need to check the'HTML source' of the page or do it the easy way by installing a SEO tool bar.
There are tons of free SEO Toolbars available for all browsers.
For instance, if you are using Chrome, you can install Nofollow by Igorware. This Chrome extension will automatically highlight all nofollowed links on a particular page.
If you do not want to install any toolbar you can check for Nofollow links manually by viewing the HTML source of a page.
Here are the steps to do this:
Step 1.) Visit the page: Open the page (that has the link you want to check), in your browser.
Step 2.) View the HTML source of the page: If you are on a windows machine simply click CTRL + U (Press 'CTRL' key first and while holding it, press the 'U' alphabet key.) on your keyboard.
Or, you can also right click anywhere on the page (using your mouse) and select 'View source' from the drop down menu.
Step 3.) Find your link: Once you are on the HTML source page, use your browser's Search/Find function to search within the page for your link.
You can access your browser's Search/Find function by clicking CTRL + F on your keyboard. Once the search box opens enter the URL of your website, eg: sitename.com and tap the ENTER key on your keyboard, until your link is highlighted on the HTML page. Refer image below:
Step 4.) See if your link has a NoFollow attribute: Check the HTML code of your link to see if a NoFollow tag is present. In the image above, you can easily tell that the link has a nofollow tag.
Step 5.) Check if the page has a NoFollow tag: You might also want to see if the page has a NoFollow meta tag present. As discussed earlier, a NoFollow can also be added on a page level.
To check for the NoFollow meta tag, open the HTML source of the page and look within the 'head' tags (<head></head>) for presence of the tag as shown in the image below. The head tags are located towards the top of the page.
As you can see from the above image, a NoFollow tag is present.
Difference between NoFollow and DoFollow links
A DoFollow link is simply a link that does not have the NoFollow tag.
Here's an example of a DoFollow link:
<a href="http://sitename.com">Link Text</a>
Now, here's the same link with NoFollow added:
<a href="http://sitename.com" rel="nofollow">Link Text</a>
By default, all links are DoFollow.
DoFollow links are viewed as Trust Votes, NoFollow links are not
You see, Google crawls the web (millions of websites) by following links (also known as hyperlinks).
When Google sees many different websites linking to a particular website, it values the website that much more.
Google views these links (DoFollow links) as 'Trust Votes'.
For example, if Website-A links to Website-B. Google takes this as Website-A issuing a 'Trust Vote' to website-B.
But if Website-A links to Website-B using a NoFollow link, Google does not see this as 'Trust Vote'. Hence the link from Website-A does not add any value to 'Website-B' from Google's perspective.
Now, Google uses links (Trust Votes) as one of its most important ranking factors. In other words, sites with many Dofollow links from other sites will be favored to rank higher in Google's search results.
Here's an analogy: if many roads (links) lead to a particular destination, then that destination must be very popular as it is well connected (well linked). Right?
In a similar fashion, websites that are well linked are considered more popular and hence viewed favorably by Google (and other search engines).
Will NoFollow backlinks negatively affect my website?
No, NoFollow backlinks will not negatively effect your website. And No, your site will not be penalized because of that.
The only thing is that, the link will not add any value to your site from the SEO perspective.
Why did Google introduce the NoFollow tag?
NoFollow tag was introduced to reduce link spamming (and thereby gaming Google's ranking system).
As I said above, Google uses backlinks as an important ranking factor. This is because Google looks at a backlink as a 'Trust Vote'. A Trust Vote should be unbiased, it should be given because you truly trust/value a website.
But not all links are created equal.
For example, I could participate in a forum and add my link in the forum signature. If I do that, my links will automatically appear each time I post in the forum. Now, does the forum 'link' to me because it values and trusts my site? Not at all, this is because the link was added by me and not the forum.
Before the NoFollow tag was introduced, Google had no other option than to consider this link as a 'Trust Vote' from the forum. But now, the forum can add a NoFollow tag to all outgoing links telling Google that these links are user generated and they don't necessarily vouch for these links.
Various uses of the NoFollow tag/attribute
You can use the NoFollow attribute on the following types of links:
- User generated links - Comment links, forum links etc.
- Sponsored links (paid links, paid banners etc.)
- Affiliate links - link to affiliate sites.
- Temporarily redirected links.
- Low quality internal links, like a link to your 'login page'.
- Block robots from crawling links on a page.
Drawback of the NoFollow tag/attribute
The one major drawback of the NoFollow tag is that it can be added to natural links given out of genuine intent.
Let's say, there is a forum and someone adds an extremely useful website link to a discussion. Most people on the thread find this link useful. What could be more organic than a link like this? The link was added not with the intent of promotion but purely because the user found the link useful. This is the best example of a natural link given out of genuine intent.
But irrespective of this, the link will be nofollowed because the forum automatically NoFollows all the links.
There is also a possibility that someone copies a paragraph or two from a website, pastes it on a forum and links back to the website as as the original source, but the link is NoFollowed. The website gets no SEO credit.
These are fine examples of how 100% natural links can have the NoFollow tag and hence get completely devalued.
That pretty much covers everything there is about NoFollow tags. If you have any further queries, feel free to ask in the comments.