Defining Toxic Backlinks

In this article we'll discuss Toxic backlinks. As you know, link building plays a significant role in SEO. Quality link building will boost your rankings: SPAM backlinks are harmful. We explained this in a previous article on how backlinks can help or harm your website.

In this article, we will show you some examples of toxic backlinks, how to identify toxic backlinks and the impact a toxic backlink can have on SEO performance.

Visualisation showing toxic backlinks linking to your website.

Toxic backlinks are a controversial topic

We use the term controversial, because experience and SEO narration are often in contrast. At times there are scenarios apparently in open contrast with so-called SEO common knowledge. But then, this is typical of SEO. Applying an SEO strategy in different scenarios can often have different outcomes. The devil is in the details.

Toxic backlinks are no exception to the general rule: SEO is more of an art than a science. You will see this as we shed new light on the dark side of link building and describe negative SEO. We describe this type of backlinks in detail and report case histories that will help you understand the complexities of backlinks, backlink profiles and link building.

What we are going to address in this article on toxic backlinks

Many new SEOs actively seek reliable information on backlinks and link building. One of their concerns is acquiring reliable information on some of the most frequently asked questions on toxic backlinks. We have compiled a list of the most important questions new SEOs have often asked us about toxic backlinks:

If you are new to SEO, almost certainly you've heard of toxic backlinks. We provide a precise definition of toxic backlinks and what make a backlink toxic. Jumping from forum to forum and article to article an SEO with little experience will quickly note how the definition of a toxic backlink can change significantly based on the context of the discussion. We'll address the burning question many junior SEOs often ask: is a toxic backlink always a toxic backlink? Another question often asked is related to the nature of a toxic backlink: where do toxic backlinks come from?

What are toxic backlinks?

Backlinks are considered "toxic" when they weaken the organic placement of a website

This is what we believe is a balanced and overall accurate definition which describes the nature and the impact of a toxic backlink. In other words, if the impact of having this backlink is positive (increase in search engine visibility) or negative (a loss in online visibility).

You will find several varying definitions on the web - we prefer to call them points of view. And this because we all have different backgrounds and different experience in SEO. Backlink analysis is truly is one of the most complex and articulated areas of SEO and for this reason one of the most challenging and exciting!

Another slightly different definition of a toxic backlink is:

A backlink that harm a website's search engine optimisation (SEO), or the ability to rank well in the search engines

Another point of view is that a toxic backlink harms the search engine rankings of a website because it is coming from an untrusted external source. The Google Penguin algorithm update in 2012 introduced the concept of an adverse backlink profile. Google enforced a strict procedure to evaluate a backlink profile inflicting severe penalties on websites with a poor quality backlink profile.

In summary, toxic backlinks are defined as unnatural links that harm the search engine rankings of a website. or, at the very least, weaken a website's SEO.

  • Weak SEO means less organic traffic from the search engines.
  • Less organic traffic means fewer visitors, a smaller number of leads and ultimately less sales.

Although there are episodes of toxic backlinks occurring organically, these are rare events. For example, a previous link building effort may suddenly have a negative impact on your SEO because the search engines may have had a change of heart on certain kinds of backlinks.

Toxic backlinks can be part of so-called negative SEO. We define negative SEO as the deliberate action of creating low-quality backlinks (SPAM link building) to discredit a website. The objective of negative SEO is to damage rankings.

Negative SEO refers to the practice of using unethical link building and other techniques (known as black hat) to sabotage a competitor's backlink profile and reduce rankings in search engines.

Negative SEO can take many different forms. In this article, we'll see an example of indirect negative SEO where hackers compromised a vulnerable website and performed industrialised link building, producing thousands of SPAM backlinks.

Where do toxic backlinks come from?

Nowadays, Most toxic links a search engine can detect are coming from SPAM sites. A SPAM website is created for the sole purpose of artificial link building. There are many SPAM websites created specifically for negative SEO strategies. Monitoring your backlink profile is essential to identify any aggressive SPAM link building. Careful monitoring of your backlink profile will allow you to take immediate proactive action and avoid problems later on. These links can also come from legitimate websites that have been hacked. For example, take notice of the links in phishing emails -they are typically coming from hacked websites. More on link building on compromised websites later in this article.

How to identify toxic backlinks

If the website hosting the link has low trust, it is a potential candidate for your toxic backlinks list. Toxic backlinks may not be high-volume in the sense that they come in large numbers. For example, they could be just a few paid links; they could be links from link schemes or link-networks.

Typical signals coming from toxic backlinks:

  • websites with low trust;
  • links with unnatural anchor text (keyword focused).

Two very important things about your backlinks and backlink profiles

  • Understand your backlink profile, then seek toxic backlinks and negative SEO initiatives;
  • Start you backlink analysis by analysing backlinks with the lowest value of Trust.

Poor quality websites harbour Toxic Backlinks

Screenshot of the Majestic Site Explorer

As a rule of thumb, good backlinks, in most cases, will have some Trust Flow which we calculate starting with a large list on manually reviewed URLs. These URLs have a crowd-sourced level of trust. By no means does this list include all the trusted sites on the web. It turns out, though, that trustworthy sites tend to link to trustworthy neighbours. Those neighbours also tend to link to trustworthy neighbours themselves. This metric, like its sister metric Citation Flow, passes THROUGH URLs as sound passes through walls – with impressive effects.

The Majestic Phrase Word-Cloud

You could have an imbalance in visible text (targeting strategic keywords, for example). This signal is a critical aspect of link building and can affect your search engine visibility. Anchor Text is the human-readable text that is associated with a link. It helps to describe and anticipate the topic of a website. This criterion is an excellent way of seeing what the web thinks of and associates to your website. It is also an indication of what people think of your brand. It is also a strong signal every search engine ranks highly in their algorithm.

Anchor text confers reputation

The clickable text of a backlink can also reflect a message that a company is pushing through acquired links, or word of mouth, which influences natural links. The Anchor Text tab in Majestic provides the text of links form the backlink profile.

 Majestic Backlinks Analyser

There is no universal definition of a toxic backlink

A toxic backlink on one site may be acceptable on another, in some cases.

While tools like Majestic can help expedite the analysis, there is no fully automated process

Take the time you need to understand your overall backlink profile. Only then will you be in a position to define what might constitute a toxic backlink for your particular site. Analysing the backlink profiles of your competitors and related websites will help you in this process and give you a better understanding of what an ideal backlink profile looks like.

For example, analysing your competitors, you might discover they too have a considerable number of low trust links - how do the two profiles compare to each other? "Bad" links may not be high-volume. They could be a handful of paid links; they could be links from link-networks, or another source. Another negative signal to the search engines could be an imbalance in your anchor text: for example, using exact-match keywords you can identify in the Anchor Text Section. Exact-match is something that, from an SEO perspective, should be avoided nowadays. Another harmful signal Search Engines can identify the abuse of guest blogging.

Start with a detailed backlink profile analysis

Download and filter backlinks from domains with close-to-zero values of Trust Flow. You can often detect a toxic link quickly, just by the URL and anchor text. It can be a slow process, but worth the investment in time and effort.

How to filter and download backlinks from backlink profiles

Site explorer view, how to filter and download backlinks

Open the backlinks tab and click on the "TF" Item of the menu in the lower part of the page as you can see in the previous screenshot. A contextual menu will open. It provides a segmented list of backlinks you can select and download for analysis. In this case, we can see there are 8,951 backlinks with ZERO. Because Trust Flow is a non-linear metric measured on a logarithmic scale, you'll notice how numbers decrease drastically from 781 backlinks with values ranging between 21 and 40 to only 40 links with a value between 41 and 60!

Fixing backlink profiles populated with toxic backlinks

Once you have identified the low-quality backlinks, you move on to the cleaning up phase of the activity.

Your objective is to identify the truly toxic backlinks

Carefully audit your list of backlinks and double-check to evaluate the quality of each link. In many cases, you may have to visit the website sourcing the backlink to determine if the link is still active or if the content is relevant to yours. Remember, you don't want to get rid of all backlinks – just the ones which, based on your backlink analysis, you consider to be of low-quality. If a site is about motorcycles while yours is about computers, they're not precisely related unless context tells another story.

A backlink doesn't necessarily have to be 100% on topic to be a good backlink

Getting back to the previous example, if your website about computers earns a backlink from a motorcycle website there is probably a legitimate underlying bond which probably triggered the link.

You'll have to make the call.

Now you're ready to trigger the disavow procedure

You Disavow backlinks if you have a manual action against your site for unnatural links, or if you think the search engines are about to inflict a manual action because of the SPAM toxic backlinks you have discovered. You'll disavow all paid links or other link-building related schemes that violate the Webmaster Guidelines. In these cases, you should first try to remove those links from the other site by contacting the webmaster. But this rarely works. If you can't get them removed, then you should disavow those links.

Create a disavow file. The disavow file is is a list of all the URLs that you want the search engines to ignore. It is a simple text file with one URL per line. A search engine will discard disavowed links in determining your website's rank and authority. Once you have created your disavow list, point your browser to this page to trigger the disavow procedure with Google.

Click Disavow Links and Choose File to upload your (*.txt) file. It can take a few weeks to process the information you upload, maybe more. One processed, it will be added to their index as they re-crawl the web. As digital marketers, we understand the importance of SEO, so we must keep a sharp eye on our backlink profiles to avoid penalties!

In Summary:

  • Download all your low quality backlinks (those with a null value of Trust Flow)
  • Identify the SPAM links
  • Contact webmasters and request removal of the link (Not practical – almost never works)
  • Disavow the links (Create a disavow file and upload to Google via your Search Console – Link)

Toxic backlink examples

Before concluding this article, we have a few real life examples SEOs have shared with us and have inspired blogposts. The articles describe the problems caused by toxic backlinks and explain how the problems were solved.

Two links to blog posts on how websites recovered from a manual penalty and a loss in search engine placement follow in the next paragraph. The first post is rather old but the principles outlined are still valid. This blogpost is interesting because it shares a full description of the penalty and how it occurred. This website suffered a manual penalty triggered by what is known as a run-of-site. Run-of-site causes a sudden, or even better an impulsive growth in the number of backlinks with SEO optimised anchor text. In this particular instance, run-of-site triggered a manual penalty. The takeaway from this first article is that the search engines monitor the growth of backlink profiles of your websites. Sudden changes may trigger manual inspections or automated SPAM penalties.

The second article addresses a different scenario where a website suffered from a sudden drop in rankings following a massive backlink profile growth, in a very short timespan. The backlinks were all NOFOLLOW coming from SPAM websites. A meticulous disavow activity proved successful, and the website recovered rankings over the following weeks.

Articles on toxic backlinks (case histories)

SPAM Backlink Profiles: The Link Scheme

Schematic of SPAM backlink profiles - a link scheme

The last example is a link scheme. At the centre is the so-called money-site.

The money-site is a website hackers want to rank high for specific transactional keywords. They will hack hundreds of sites and install a parasite mini-website with thousands of pages all linking to the money site. In a matter of days, the money-site will rank on the search engines and generate revenue, thanks to hundreds of SPAM backlink profiles. The money-site may rank highly with superb organic placement in the search engines for a few days or weeks - and make money. The search engines will eventually discover and de-index. By then, it will have generated enough revenue, and the hackers will move on to another link scheme. In this example, the website was about NO-SQL databases - you can see how the backlink analysis with Majestic quickly identified the off-topic anchor text while performing an SEO audit. Backlink analyses are always an integral part of an SEO audit. The unforeseen and unpredictable is sometimes just a click away!


In this article, we have examined backlink profiles in great detail to understand the origin and nature of toxic backlinks. We have discussed the many aspects of link building related to toxic backlinks and backlink profiles. You have learned about implementing and executing negative SEO and the consequences of a negative backlink profile for SEO. We have briefly introduced the concept of toxic link disavowing and described how a disavow file is created and uploaded to have the search engines ignore these links.