Nofollow Tags: What They Are and Why They Matter

Nofollow links are a tactical tool. Use them to prevent comment spam on your site, and to help maintain your authority.
Article Outline

Have you ever heard web experts or SEOs talk about nofollow links? It’s a concept that was developed as a defense tool for website owners, but it’s also a tool that search engines use regularly. Here’s the background:

There are several reasons why a website would want its users to be able to add links to a site (while preventing them from driving value from the website to another site), or instances when a website wants to link out to a site but not share authority. The nofollow link makes that possible by telling a search engine that a link does not have value.

Circa 2005, search engines and businesses were dealing with many consistent spam issues. Some of those included:

  • The World Wide Web was to some extent a link-buying economy; some companies’ entire business models were based on paid links that could give them the rankings they wanted.
  • Content spam was prevalent. That’s content that exists only to give context for advertising, or a link. It does not usually serve the average reader well. Many types exist and were used at the time.
  • Comment spam. This is found in comments on forums, blogs, wikis, and online guest books; usually the comment exists only for some link to be embedded in.
  • Link spam: Any links whose purpose was solely to improve a website’s ranking in search engines by controlling some of the flow of PageRank from one website to another. Many types of link spam exist.

That’s just a tiny slice of the spam pie that existed then. Google’s Matt Cutts and Jason Shellen (Blogger, Google Reader, Brizzly, et al.) wanted to figure out how to change the Google algorithm to better identify spam links, so they could stop the engine from giving these links value.

That’s when the nofollow tag was born.

A link with a nofollow tag tells search engines “don’t follow this specific link”, essentially saying “we aren’t sharing our authority with this website, but we want users to navigate to it”.

A nofollow link includes a nofollow tag. Nofollow tags are an attribute tag (rel=… ) that is placed within the HTML of a hyperlink, like this:

Link value is at the heart of why this type of tag was needed in the first place. Your links help share valuable signals to search engines through anchor text, the authority of the website linking out, placement, relevancy, and other trust factors.

Search engines use these signals to give them more context about how they should value the webpage in addition to the website as a whole. Today they look at things such as social signals, semantic relevancy, and much, much more, but links have been used longer than most signals today. They’ve been used for years as the main “oil” that runs the Google “engine”.

Nofollows and Google penalties

It might sound strange now, but it used to be that some organizations paid black-hat SEO companies to post comments that contained links back to the organization on other sites. At the time, search engines assumed those links passed valuable signals, so this strategy was aimed at ranking your website better. (And it used to work.)

Today these types of activities may result in a Google penalty instead of the benefits seen in years past. If you know anything about the Panda and Penguin penalties then you know the depth of action Google took (and continues to take) to continue dealing with this type of spam. While the nofollow attribute tag didn’t fix the problem completely, it did add to the collective toolbox of ways to mitigate spam.

Uses of Nofollow Tag

User-generated content on your site is the first place where spammers look to infiltrate your site and control links. If they get link-laden content into your pages (and those links point to spam websites), they can cost you link authority.

Comments, guest authors, press release submission, video submission, reviews and forums are a few common user-generated content functionalities seen on websites. They are also the easiest to use for link-building manipulation.

You could moderate your forum, adding nofollow tags to the content that doesn’t pass muster, but that’s labor intensive. Your best defense is a universal nofollow setting for those types of activities. Make all user comments nofollow, or any guest content adding a nofollow tag to links, in a forum creating all links with a nofollow tag, or press release submissions automatically having nofollow tags on your site.

  • Comments: In many (if not most) content management systems, you can set all comments to be nofollow. It’s a recommended practice.
  • ECommerce: In the bad old days, some sites made money by getting paid for putting links on their sites. If you’ve got an eCommerce site with a lot (hundreds, thousands) of outbound links, your pattern of links may look like that spam pattern. Consider using nofollow on most of them to protect yourself from being seen or viewed by the search engines as a site selling links.
  • If you link to content or embed something (say a widget or infographic) but you don’t want to be perceived as endorsing the site you’re linking to.

A common misconception is that the nofollow tag tells a search engine not to crawl/index the page being linked to. A search engine can still be led to that site or page, crawling and indexing it. The nofollow refers to the value that is passed, not the functionality of indexing. This is important to note for things like thank-you pages on websites. A nofollow tag isn’t the best way to ensure those pages aren’t indexed, instead a noindex tag on the page is more appropriate.

Value of Nofollow Tag for Rankings

Nofollow links still have the ability to affect your ranking. These links are “valueless” from an authority perspective, but they still have their uses.

  • Semantic Value  The words used as anchor text and words surrounding a hyperlink aid a search engine in understanding meaning for a website even when a nofollow attribute is used.

All this information goes into a big ol’ “bucket” for a search engine to use as intelligence. In a natural backlink profile it’s expected that some nofollow links will show up, and those links can be used to help with semantic signals. This may lead to a diverse amount of keywords ranking, not just one primary word.

  • Relevancy  The relatedness of the website linking to you and the words used are important signals sent, even from a nofollow link. Irrelevant and unassociated words to your site on a page with a nofollow link can still throw off a search engine. The reverse is also true, that relevant and useful words from nofollow links can send signals too – for positive use.
  • Natural Profile  As stated before, nofollow links are expected in backlink profiles. It’s actually unnatural not to see any nofollow links for a website. Don’t get scared about building nofollow links, they still act to provide a very natural profile for a website.

Add a nofollow tag by using rel=nofollow as shown below. Site-wide changes could then be made to links pointing out from a website from certain pages or cherry-picked areas of a site.


The nofollow link attribute tag was an amazing invention to help mitigate spam online. When used properly, it can help a website follow best practices and help reduce spam propagation. We encourage anyone reading this article to look internally at your own use of nofollow. Are you using it properly? Take swift action today to fix any practices you’re currently doing that limit the effectiveness of this wonderful tag.

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