When Google founders Larry Page and Sergey Brin wrote their first search algorithm in 1996, it was built on the idea that when websites link to one particular website, that website must be authoritative and high quality.

Over the past 23 years, Google has updated their algorithm thousands of times. In 2018 alone, they reported 3,234 changes to their algorithm. Those changes have made Google’s algorithm much more sophisticated. Despite all of those changes, links between websites, or backlinks, are still one of Google’s top ranking factors.

Even though Google hasn’t changed the importance of backlinks, they have introduced different types of backlinks that determine how the search engine handles links between websites.

When you get down to it, there are only two types of backlinks: dofollow and nofollow. A person reading a web page will never see the difference between a dofollow and a nofollow backlink. The difference is in the source code. There’s a specific tag in the source code that determines how Google and the other search engines view the backlink, which also determines the effect of that backlink on your SEO profile.

Dofollow backlinks are the most common and valuable type of backlink for SEO.

When you put a dofollow link on your website, you’re telling Google that the link is organic — as in, the target website didn’t buy the link—and that you’re vouching for the accuracy of the content at the other end of that link.

Dofollow is simply telling Google and the other search engines that “the content on the other end of this link is important and should be noted.”

For example, this link is a dofollow backlink to our friends over at Internet Marketing Ninjas. The source code for that link looks like this:

Notice how there’s nothing different about that link? It’s just a regular link. That’s one of the reasons that dofollow links are the most common — they’re the easiest to put in place.

nofollow

Nofollow backlinks are less common. They’re also less valuable. They’re used to tell search engines to ignore a particular link.

Google’s official definition of the nofollow tag is, “‘Nofollow’ provides a way for webmasters to tell search engines ‘Don't follow links on this page’ or ‘Don't follow this specific link.’”

The HTML markup for these links is similar to dofollow links, with one big difference — the “rel=nofollow” tag. If we used a nofollow link on our example from above, it would look like this:

The percentage of dofollow versus nofollow links that a website has will vary. Google wants to see a good mix of both for a healthy link profile.

The biggest difference between these two types of links is that Google places a lot of value on dofollow links — which means they’re great for SEO. Nofollow links, on the other hand, are ignored by Google’s algorithm in most cases. That means they’re rarely valuable for SEO.

Despite the fact that nofollow links are less common than dofollow links, there are still plenty of places on the internet to pick up nofollow links. You’ll most often get these types of backlinks from websites where you can upload your own links and content, because those websites don’t want to vouch for the accuracy of your content.

Here are a few places that nofollow links commonly come from:

  • Social media websites, such as Facebook, Twitter, and LinkedIn
  • Blog comments
  • Content aggregation websites, such as Scoop It
  • Q&A websites, such as Quora
  • Forums, such as Reddit
  • Press releases

In addition to all of those, many high-authority websites, like Wikipedia and the Huffington Post, use nofollow links to reduce the number of spammy backlink requests they receive.

Surprisingly, nofollow backlinks do provide some SEO value.

Google’s official stance on nofollow links is, “In general, we don't follow them.” That means that Google doesn't follow the nofollow links most of the time, but there are certain circumstances in which Google does follow the links. It’s hard to say what those circumstances are, because Google hasn’t shared that information. That's why the SEO community has done a lot of testing to identify a few instances when nofollow links are followed.

High-authority websites

There’s some evidence that nofollow links from high-profile websites, like Wikipedia, can improve your organic rankings.

The thinking is that there are websites that Google completely trusts. Those websites are known for content that is extremely high quality. That means if those websites are linking to another website, that linked website is also valuable. In that case, Google will somewhat ignore the nofollow link.

It’s unlikely that they’re completely ignoring the nofollow tag in those cases. If you were to pick up a dofollow link from Wikipedia, that would still be much more valuable than a nofollow link from the same source.

There are probably very few websites that fall into this category.

Adam White, the creator of SEOJet, wanted to find out how nofollow links affected SEO. He went to one website that ranked for a number of SEO terms and paid for them to place a nofollow backlink to his website. He asked them to use the anchor text “backlink software” because his website didn’t rank on page 1 for that keyword. He also made sure that no other links pointing to his website had that anchor text.

The use of that anchor text is important because anchor text helps Google understand what your website is all about when someone links to your website using specific keywords in the link.

Within a week of the nofollow placement, SEOJet’s website shot up to the number one ranking for that keyword.

It is possible that the timing is a coincidence, but Adam claims that the nofollow link was the only change he made to his website during that period. It’s worth pointing out that this is just one test and not something that’s guaranteed to work, but it’s worth testing further.

Luckily for us, that’s exactly what Rand Fishkin did. He ran a test in which he asked a number of website owners to link to a specific web page using a nofollow tag. The results weren’t huge, but they did show a slight increase in rankings.

The target web page for his experiment went from the ninth spot in Google’s SERP, up to the sixth spot. A three-spot improvement isn’t huge, but it is still surprising, considering that Google claims it doesn’t take nofollow links into account.

Perhaps the biggest reason you’ll want a nofollow link is the indirect benefits of gaining one. According to Fractl, one nofollow backlink from a highly trafficked website can result in plenty of dofollow backlinks. That’s often because content creators use those highly trafficked websites to research their own content.

Fractl proved this by getting a nofollow link to a piece of content from a Yahoo article. Once that Yahoo article was published, Fractl’s content gained an additional 700 backlinks from other websites — two-thirds of which were dofollow links.

The other indirect benefit of nofollow links is that those links still pass traffic to your website, which is obviously better than no link at all.

To sum it up, we don’t have any concrete evidence to say that nofollow links are good, but there is enough anecdotal evidence to prove that they aren’t bad. If you’re planning any link-building campaigns, don’t ignore the websites that only give out nofollow links, especially if they’re bigger, high-authority websites. They’re still valuable in terms of traffic, exposure, and even a bit of SEO.

For the most part, you’ll want to use dofollow links when linking to other websites from your website. As long as you’re linking to valuable resources that help your readers, there’s no reason not to use a dofollow link.

If, for whatever reason, you’re linking to a number of low-quality websites, you might want to consider using a nofollow tag so Google doesn’t think you’re vouching for the quality and accuracy of those low-quality websites.

That isn’t the only reason you’ll use a nofollow tag, though. According to Google, there are three other situations in which you’ll want to use nofollow links.

1) You don’t have control over what gets posted

If you have a forum or comments section as part of your website, you’ll want to nofollow all links that people post there. This will help reduce spam comments on your blog or forum. If people know they can’t get dofollow links from your website, they’ll be less likely to post a ton of irrelevant links.

Hacker News does this perfectly. The main links from their website are all dofollow, but the links in the comments are all nofollow.

The links that are highlighted in green — the link to the main content and internal links — are all dofollow. The top comment, which includes an external link, is highlighted in purple because it is a nofollow link.

Backlinks are supposed to be organic. If someone paid you in some way to promote their website, you need to nofollow that link. That will help search engines understand that the link isn’t valuable for organic search because it was manipulated.

If you don’t nofollow a paid link, Google could penalize you. Here are all of the types of links that you should nofollow:

  • Link-for-money exchanges: If someone offers to pay you for a link from your website, you need to nofollow that link.
  • Product-for-link exchanges: If someone sends you their product to try out in exchange for a link, you must use a nofollow tag on that link.
  • Link-for-link exchanges: If someone offers to link to your website if you’ll link to theirs, you better nofollow that link.
  • Keyword-rich anchor text link guest posts: Guest posting is generally okay, except when the post has an excessive number of dofollow links back to the author’s website. You need to nofollow those links.
  • Contract-required links: If your customer contracts require that they link back to your website, you better make sure they’re nofollowing those links.

Essentially, if you’re linking to another website for any nonorganic reason, you’d be safer to use a nofollow tag. You don’t want to get penalized by Google for a simple link-tag mistake.

3) You’re worried about crawl prioritization

Crawl prioritization is generally something that only very large websites have to worry about. If you have a huge number of web pages, Google might have trouble figuring out which are the most important pages to index.

If you have pages on your website that are noindexed, any internal links to those pages should be nofollowed. That will keep search-engine bots focused on the parts of your website that matter.

For example, let’s say you don’t want search engines to index your login page. Any links on your website that direct users to that login page should have the nofollow tag.

If you’re not sure about the types of backlinks that certain web pages are using, there are a few easy ways to check.

First, you can take a quick look at the source code. We’ll use the same example from Hacker News.

If you’re using Google Chrome, right-click anywhere on the web page and select “View page source.” From there, find the link in the HTML of the page. If that link has a nofollow tag, you’ll see it right after the URL.

For the Hacker News example, the Imgur link has the rel=“nofollow” tag right after the URL.

That process, while simple, isn’t always guaranteed to work. Some websites are built in a way that won’t allow you to understand the HTML. The Q&A website Quora is a good example. The page itself looks like any other content page that you’ll find on the internet.

You can’t tell whether those two links are nofollow or dofollow. If you look at their source code, it’s unreadable and unsearchable. You won’t be able to find the content or the links anywhere in that source code.

When you run into websites like that, you can use a Chrome plugin such as NoFollow or MozBar to highlight the links that have the nofollow tag.

Here’s what that looks like using MozBar on a Quora page:

The two links in that screenshot are highlighted in purple because they’re nofollow links. If they were dofollow links, they would be highlighted in green.

As we mentioned earlier, dofollow backlinks are the most valuable. They’re the ones that make a big difference for your SEO. That’s why it’s important to always search for ways to get more dofollow backlinks.

There are a number of ways to get dofollow backlinks by creating content. You can take a page from Rand Fishkin’s book and create 10x content, which is content that is 10x better than any of the top-ranking articles for that keyword. If you’re able to pull that off, you should gain backlinks organically.

You can also get backlinks by writing high-quality posts for other websites and including a link back to your website. As long as you use only one or two dofollow links in your guest post, you won’t run the risk of being penalized by Google.

If those two are working well for you, consider creating and publishing some original research. That’s a great way to get backlinks, because other authors will cite your research in their content.

If you’re already doing all three of those techniques, below are a few ways to get more dofollow backlinks that don’t require you to create more content.

1) Testimonials

You probably use a number of services, tools, and agencies to run your company. Chances are good that those companies have some sort of testimonial or case-study page on their website.

If they do, reach out and offer a testimonial or case study about their product. Most of the time, they’ll link back to your website in part of the testimonial.

Here’s a perfect example from Productboard:

That page is a case study that includes a dofollow link back to their customer, Slite.

2) Top X lists

In just about any industry, if you search for “top X <keyword>,” you’ll find listicle blog posts, which list a number of resources or companies that their readers should know about. If you come across a list like this that your company, product, or content isn’t on, reach out to the author and see whether they’d be willing to include you.

For example, let’s say you work in the medical-device industry and are putting on a conference. You want your conference web page to rank highly, and the best way to do that is to gain backlinks.

In that case, you’d search for “top medical device conferences.” You’ll see the first result is this one from Greenlight Guru.

From there, reach out to the author, Nick Tippmann, to find out whether he’d be willing to add your conference to that list.

You can repeat this exact process for just about any topic in your industry. Chances are, someone has written a listicle post about it.

3) Help a Reporter Out

We first heard about this technique from Backlinko, and it does take time and effort, but it really works.

The website, Help a Reporter Out (HARO), was created to connect journalists with experts. Once you register, you’ll get an email each day with a list of questions that reporters need answered. If you know the answer to a question, all you have to do is reply, and then you might end up with a high-quality backlink.

A lot of marketers use this technique, which means the reporters usually get a lot of responses, and they obviously can’t use all the responses. That’s why you need to give your best possible answer when replying to reporters’ questions. Spend time thinking about it and writing your response. You’ll have a much better chance of getting a featured quote if your answer is insightful and helps the reporter fill out their article.

Even if the reporter doesn’t include a backlink to your website in the published article, HARO is still a great way to get media coverage.

This technique is time-consuming but can work really well. The idea is to find websites that are linking to content similar to yours, but, for one reason or another, their link to that content is broken.

When you find instances like that, reach out to the site owner or author and tell them about the broken link. Then, mention that you have a resource that might be a better fit for that link anyway.

Site owners will want to fix broken links because they’re bad for user experience and bad for SEO. You’ll be helping them out by doing broken link building.

The best way to do this is by finding websites that are in your industry but aren’t competitors. Run their website through a broken-link checker, which will identify any broken links on that website.

When that tool returns a list of broken links, sort through the list to find places where your content can take the place of the broken link’s content. Then, reach out and let the site owner know about the broken link and suggest your content as an alternative.

The two types of backlinks are both important to your website’s overall link profile. Google wants to see a healthy link profile that consists of both nofollow and dofollow backlinks.

Too many nofollow links from low-authority sites might suggest to Google that you’re just spamming your content on the web. But too many dofollow backlinks could look just as suspicious, especially if they’re coming from low-authority websites.

While it’s important to understand the difference between these two types of backlinks, don’t focus too much on getting one type or the other — they can both be beneficial. Just focus on building links and let Google handle the rest.