Backlink Analysis: How to Spot Quality and Toxic Backlinks

James Brockbank

Apr 24, 202023 min read
Finding toxic backlinks

Backlinks remain one of Google’s top three ranking factors, which means you simply can’t ignore the need for a solid strategy to earn these. Without building high-quality links, the reality is that you won’t rank highly for competitive keywords and search terms.

Not all links are equal. In fact, the wrong type of links can harm your website and negatively affect your rankings, impacting organic traffic, and revenue as a result.

You should be analyzing your backlinks and your competitors’ on a regular basis to find fresh opportunities to build links that will help increase your organic visibility, to identify any issues which could be holding back your site’s performance, and to discover the most appropriate way to take action to resolve these.

What This Guide Will Cover

If you are not regularly analyzing your backlink profile, it is something you need to start doing. The more insights you have on both your and your competitors’ link profiles, the better chance you have to use this information to improve your strategies.

Conducting a backlink analysis helps you to understand the link gap between you and your main competitors. By understanding the quality of your own link profile and your competitors, you are able to identify your ability to rank against others and see how difficult it will be to outrank them. This means you can develop a strategy that will close the link gap and help you gain a competitive advantage.

Without insight into the link profiles of the sites you are competing against, you will be working blind. A really quick way you can do this is by comparing up to five domains with the SEMrush Backlink Gap tool:


The more you know how you stack up against your competitors, the better your strategy can be, and the easier it will be to find opportunities to build links that positively impact your rankings.

The wrong type of links (often referred to as bad links, toxic links, spammy links or unnatural links) can harm your site’s organic performance, and running a backlink audit is the most effective way to proactively find these issues and areas of concern so you can take action to protect your rankings. 

If you have been unfortunate enough to already have seen a negative impact as a result of bad links, you will need to carry out an analysis to fix the issue and regain your lost rankings.

To put it simply, you can think of a backlink analysis like a routine health check or an MOT on your car; and when you do it regularly, you can fix potential problems before they cause issues.

Quality links come from trusted sources and are not, in any way, intended to manipulate search engine rankings. To understand what these look like, the best place to turn is Google’s Webmaster Guidelines.

In fact, Google directly tells us

 the best way to get other sites to create high-quality, relevant links to yours is to create unique, relevant content that can naturally gain popularity in the Internet community. Creating good content pays off: Links are usually editorial votes given by choice, and the more useful content you have, the greater the chances someone else will find that content valuable to their readers and link to it.

We can simplify this, though. High-quality links are those that have been editorially placed as a result of someone finding your content valuable and choosing to link to it. 

When a link is editorially placed, this is done by a writer or webmaster because they took the decision to do so. They didn’t have to link, but they chose to because you have created a valuable piece of content that they want to amplify or use to help their readers. And it is this that we need to pay attention to and really understand.

The reason why digital PR and content marketing have become such popular link building tactics is that they directly result in journalists, editors, and other publishers choosing to cover a story or piece of content and link to it. These tactics help you build high-quality links and avoid the risks associated with toxic links. 

Aside from being editorially placed, a high-quality link…

  • Have the potential to send referral traffic. If you would still want a link if Google didn’t exist, there is a good chance this is because there is an opportunity or the potential to receive targeted referral traffic. Let’s not forget that links are primarily navigational in purpose, and if a link could drive quality traffic to your site, it is likely a good one.

  • Topically aligns with your own website’s content. There are few things more unnatural than links between two pieces of totally unrelated content. Quality links come from other web pages that cover a similar topic to your own.

  • Comes from a trusted source. Links are a vote of trust from one website to another, and the highest quality links come from the most trusted sources. Put another way, you will trust a recommendation from a friend over a stranger any day, and the same can be applied to backlinks. A link from a trusted site, such as the New York Times, is ultimately a higher quality link than a blog that no one has ever heard of — and that has no clear topical steer and is producing low-quality content. 

A great example of a high-quality link that ticks all three of these boxes is this link within an article on Auto Express (an automotive publication) which points to a study by Compare the Market that reveals the cheapest and most expensive locations to get car insurance:


If we can outline quality links as those which are editorially earned, come from trusted sources, and have the potential to send referral traffic, what is a toxic backlink?

Again, let’s turn to Google and their  link schemes guide that clearly states: 

Any links intended to manipulate PageRank or a site's ranking in Google search results may be considered part of a link scheme and a violation of Google’s Webmaster Guidelines. This includes any behavior that manipulates links to your site or outgoing links from your site.

If Google considers a link to be an attempt to manipulate your search rankings, it violates their Webmaster Guidelines. But just what type of links are manipulative?

In a very simplistic form, those which are not editorially placed and which an SEO has actively placed with the primary purpose of increasing search rankings. Toxic backlinks commonly display signs of low quality or an attempt to manipulate rankings such as:

  • Coming from sites that have been set up only for the purpose of linking out.

  • Coming from sites and content which aren’t topically relevant. 

  • Coming from sites that aren’t indexed by Google.

  • Being obviously forced into blog comments.

  • Being hidden away in a website’s footer.

  • Existing on every page on a website.

  • Using ‘ exact match anchor text’ (using commercial ‘money’ terms and target keywords as the link text).

  • Followed links clearly marked as sponsored.

These signs of bad links, and more, are what contribute to SEMrush’s toxic score — a handy tool which you can use to discover and analyze toxic links before attempting to remove or disavowing those deemed to be unnatural. 

You will learn how to run a full backlink audit to help you find toxic links shortly. 

There was once a time when the use of manipulative links was commonplace, and they had a profound impact on a website’s rankings. Google’s algorithms have evolved extensively in recent years, and their efforts against web spam (the wider topic which unnatural links fall under) are widely reported.

Traffic losses due toxic links

In 2020, successful link building is about focusing on quality over quantity, and low-quality links can significantly hurt your rankings and organic traffic. Unnatural links were the target of 2012’s Google Penguin algorithm update, one which changed the link building landscape for the better. 

But let’s talk about how toxic backlinks can harm your site’s SEO efforts today, looking at the three scenarios.

If someone at Google’s webspam team reviews your domain’s link profile and finds excessive spam, they may apply a manual action for unnatural links. In Google’s own words:

Google issues a manual action against a site when a human reviewer at Google has determined that pages on the site are not compliant with Google's webmaster quality guidelines. Most manual actions address attempts to manipulate our search index.

Manual actions are far less common than they once were. It takes time and resources to review a site manually, and, as such, Google has put in tremendous effort to better identify bad links with its algorithm. That said, manual actions can still happen, especially if you are repeatedly excessively spamming. 

Manual reviews can be triggered by:

  • A competitor filing a spam report.

  • Issues detected algorithmically, which trigger a review.

  • Being in a niche that is known for excessive link spam.

You will know that you have received a manual action (penalty) because you will receive a notification in Google Search Console. It will be in the ‘manual actions’ tab:

Manual action section in Google Search Console

If you have received a manual action, you will see a sample of the affected pages — these can either target sections of your site or be applied sitewide. Typically, you will find that the pages that are affected will lose any rankings they held before the penalty was applied, and they will be prevented from regaining those rankings until it is lifted.

To remove a manual action from link spam, you need to make an attempt to remove the toxic links that caused the penalty (or request that the webmaster adds a nofollow, UGC, or sponsored attribute to these) and disavow any which you can’t, before filing a reconsideration request. You can learn more about how to file a request  here.

Your Site Suffers From An Algorithmic Filter

Perhaps the most common scenario caused by toxic links is that your site suffers from an algorithmic filter (often also referred to as an algorithmic penalty or adjustment). This is where the algorithm applies an adjustment to your rankings, having detected unnatural links, rather than a human.

Typically, when the adjustment is related to bad links, this is done by the  Penguin filter. 

You won’t receive a notification to say you have been affected, and you can’t file a reconsideration request to remove an algorithmic penalty. However, it is common for Google to make a public announcement that there has been an algorithm update, and you will often see lots of  Sensor volatility.

Organic Changes

That said, you will usually know when you have been negatively hit in this way, as you will see a significant decline in organic traffic and visibility. This may be sitewide, or the decline may come from a set of pages or site sections, depending upon the extent of the unnatural links.

To recover from an algorithmic filter caused by toxic links, you need to stop the tactics that caused the issue and disavow those links which you suspect to be problematic. The likelihood is that you won’t recover rankings to where they were before the adjustment, as your site was unnaturally held up by bad links.

You will need to go out and earn better links to fully regain the lost ground.

Google is getting better at ignoring unnatural links. In fact, in 2019, John Mueller even stated that Google ignores links from sites where there are unlikely to be natural links.

He even went so far as to suggest you don’t need to disavow these links. This is, in some way, the good news — there is less of a chance that unnatural links will cause either algorithmic or manual penalties.

You are increasingly unlikely to see severe action unless you are spamming to a serious extent. That said, this means any links that are being built that Google is choosing to ignore are simply having no impact on your rankings at all. What a waste of resources (and, likely, money)!

You need to understand the impact of each link you are building, either in-house or via an agency, and consider that Google may simply be ignoring them if they are deemed to be low quality. 

It is critical that you be aware of the link building tactics that can lead to toxic backlinks, and below is a roundup so that you can be sure to stay away from these, as well as spot potential issues when carrying out a link analysis.

When money changes hands in exchange for a link, you are straight-up violating Google’s Webmaster Guidelines. It is as simple as that, and this includes paying sponsorship fees for guest posts, as well as gifting products or services in exchange for a link. If a link is paid for, it has not been editorially placed.

But while it is a no-go from an SEO perspective, if you are using sponsored content for reasons other than building links (to leverage someone’s audience and earn referral traffic, let’s say), be sure to add rel="nofollow" or rel="sponsored" attributes for full transparency and avoid the links being identified as unnatural. 

Links that use exact match (keyword rich) anchor text are often toxic, largely regardless of the source. 

Just think about it this way...

Most people wouldn’t naturally link to an online shoe store using a link text of ‘buy cheap shoes.’ They would be far more likely to link using the brand name or domain. If there is excessive use of keyword-rich anchor text, it is a potential flag that you are paying for links or that they are not editorially placed.

If you are influencing the anchor text, which is used to be an exact match to the keywords a page is trying to rank for, the links are unnatural. 

See the link to ‘long term dog boarding’ in the example below? That’s an exact match anchor text.


Private Blog Networks

A private blog network (PBN) is a black hat link building tactic that involves building and maintaining a collection of sites that are used for the primary purpose of adding in links to other sites — they are usually developed from expired domains, which are repurposed. 

Many black hat SEOs would argue that a truly private blog network would never be discovered by Google. However, the issue is that many are easy to spot by experienced SEOs and, therefore, Google themselves, even when they may appear to be natural to an everyday web user.

That said, using PBNs to build links results in unnatural links, and Google has actively been pursuing closing down such networks for years, with high profile instances as far back as 2014. Google will eventually discover pretty much any PBN, and, often, the penalties imposed can be severe.

As Nathan Gotch comments on GotchSEO

“Not only did Gotch SEO get nailed for using PBNs, but so did several of my clients. Before that happened, I thought I had complete “control” of my SEO because I was in control of my backlinks. It’s crazy how wrong I was. But sometimes you need a rough moment to change your ways.”

PBN links can be hard to discover, and they are often combined with other link spam signals such as exact match anchor text links due to the control the site owner has. Again, these aren’t editorially placed.

If you have previously bought links that you know come from a PBN, strongly consider either getting these removed or adding them to your disavow file. While some may debate that some PBNs works and drive traffic, I will say there are always rare exceptions. However, for the most part, you want to avoid this practice. 

Back in the late 2000s and early 2010s, building links using spun content was a popular tactic. 

The tactic involved writing one article and then using software to spin this into hundreds of different variations — all of which usually ended up as garbage. These articles would then get uploaded to article directories (anyone remember eZineArticles?) with links included within these. Here is an example:

Example of an ezine article with exact match backlinks

Notice the use of exact match anchor text?

There’s absolutely no value to be gained from this article and it is clear that the only reason it was published was to link back (twice?!) to a promotional gifts retailer. 

These links are pure spam and this tactic should be avoided at all costs, with historical links like this cleaned up.

Another legacy link building tactic that is associated with toxic links is comment spam. These comments are often automated using software that places large numbers of irrelevant comments on blogs (again, often using exact match anchor text). The hope is that some go through without moderation, and the goal is simply to try and land as many links in comments as possible.

If you run a WordPress site, there is a good chance you get plenty of notifications with comments to approve, which seem completely unrelated to the content, but that includes a link. That is comment spam.

The same tactic is often applied to forums, posting comments and responses in threads with nonsense replies but which include links. In fact, Google even shares an example in their link schemes guide:


Not only do these links have no value, but they also leave a footprint that Google’s algorithms can (and will) pick up on due to using either the same or very similar comment variations, all pointing back to the same page. 

Avoid this tactic at all costs and work to clean up any historical links built like this. 

Low-Quality Directory Submissions

Let’s clear one thing up — directory links sometimes get a bad reputation, full stop. And this is very much an "it depends" situation.

If you are listed on real directories that offer actual value to users, you are not running any risk, and these can often be really good links, so long as they are topically aligned to your business. This means that the directory is either niche-specific or localized to your local area.

The example below is from the New York Chamber of Commerce. It is a directory of members, and you are not about to get penalized or see links marked as toxic for appearing on a site like this:


But compare this to the image below:

Image of a spam directory with backlinks

This is a low-quality directory that has absolutely no value to users. In fact, browsing through the site, it is clear that there is no targeting whatsoever in terms of niche or location-specific:

example of a low quality directory

Avoid building low-quality links like this. They offer no value and could do far more harm than good.

That said, if a directory offers value in terms of inclusion alongside others in your niche or the local area, they may be worth considering, but not as a tactic to build significant numbers of links — just on a case by case basis for reasons beyond just landing a link. 

Scaled Guest Posting

To be clear, guest posting isn’t necessarily a tactic that results in spammy links. Often, far from it. However, SEOs turned to guest posting at scale after the Penguin algorithm launched, often publishing low-quality content anywhere that would take it, even if the sites were completely unrelated.

There were even whole platforms in existence (remember My Blog Guest?) simply for the purpose of exchanging guest posts with others. In January 2014, Google’s Matt Cutts declared guest blogging dead, highlighting, “Okay, I’m calling it: if you’re using guest blogging as a way to gain links in 2014, you should probably stop. Why? Because over time, it’s become a more and more spammy practice, and if you’re doing a lot of guest blogging, then you’re hanging out with really bad company.”

Today, Google’s link schemes guide includes the following as a violation of their guidelines:If you are using guest posting to build keyword-rich anchor text links on sites that have no topical alignment and, in reality, offer no value to you outside of the link, you are building toxic links as a result.

That said, you could class writing for an industry publication as a sector expert as guest posting, writing a column each month. As this isn’t being done at scale — it has the purpose of building your brand positioning before links and is topically related; this remains a valuable tactic. 

If you are developing a widget or plugin (let’s say, for WordPress) and distributing this with a link included alongside it (once upon a time, this was common to see in sidebars all across the web), you are violating Google’s Webmaster Guidelines and building toxic links:

Links in widget plugins a violation of Google Guidelines screenshot

If you have done this in the past, it is time to clean up these links. But, be warned, there could be tens of thousands of them! 

While reciprocal link building often naturally happens (two sites linking to one another), if this is done at scale and the links come from largely irrelevant ‘links pages’, then you are going to end up with a bunch of unnatural links as a result.

Offering to link to a site if they link to you doesn’t deliver editorially placed links, and its a tactic best to be avoided in 2020. 

Many wrongly assume that they can only be penalized for spammy inbound links, but that is not the case. You can also be penalized for linking out in an unnatural way — for reasons including accepting payment for links that pass PageRank, excessively using keyword-rich anchor text, and more.

This great guide from Tony Edward on Search Engine Land tells you more about how to avoid falling foul of Google’s guidelines for toxic outbound links.

Every SEO needs to be checking for toxic backlinks. Some do this routinely or others after seeing a drop in rankings or receiving a manual penalty.

I will talk show you how to use SEMrush’s  Backlink Audit tool to discover spammy links that point to your site. 

Step 1: Set Up Your Audit

When it comes to setting up your audit, it is recommended that you analyze the root domain (unless you are specifically looking at a subdomain) and specify your brand name, and then set your target country and category. These last three are optional and should already be filled out, but it is good to check them over.


Start your backlink audit and wait for the confirmation (by email) to come in to let you know it is finished.

Step 2: Connect Google Search Console

While you are waiting for the audit to complete, you will need to connect SEMrush to your Google Search Console account to be able to submit a disavow file and gain further link insights. You will need to be a verified owner of the property to do so, as you will need to share access to the account with a SEMrush email address.

You should then see a successful connection confirmed.

finding toxic backlinks graphic

Step 3: Get A Quick Overview and See Results

Once the audit has completed, you will see a quick overview as to the stats and an indication of the overall health of your backlink profile.

Screenshot of a completed backlink audit

It is time to view the full results and dig deeper into the audit findings.

You’ll now see an overview into your site’s backlink profile:

screenshot of a site’s backlink profile

At this stage, you want to pay attention to the overall toxic score. In the example above, there is a medium toxic score rating given, which indicates there is some potential cleanup needed. 

Head straight into the ‘audit’ tab.

Step 5: Begin Auditing Your Toxic Backlinks

Make sure you have got the results sorted by ‘toxic score’ so you can work through the links based on those deemed to be the most toxic. 

Toxic Score is how the Backlink Audit Tool determines which links pose the most potential harm to your site’s rankings and is based on a scale of 0 to 100, with 0 being good and 100 being very toxic — it uses over 50 toxic markers.

Check the link's toxic markers before making a decision about what to do with it next.

Showing toxic markers for links in the semrush tool

You need to work through your backlinks and determine the action to take. However, it is strongly recommended that those with a high toxic score are either removed or added to your disavow file. 

Step 6: Create Your Whitelist

To keep things clean, you want to create a whitelist that includes domains with a low toxic score or which you know to be natural and safe. 

You can add links to your ‘keep’ list once they have been selected.

Whitelist links option

You should now be left only with those which you’ve determined you need to take action on. 

Once you have created your whitelist, you will be left with domains that are deemed to be toxic. Now it is time to take action on these links to clean up your link profile and improve your toxic score.

If you have received a manual action, you will undoubtedly need to make an attempt to remove a substantial amount of toxic links. If you have not had an action and are either doing a routine cleanup or have seen an algorithmic filter applied, you may want to skip this step and jump straight to learning how to disavow.

Step 1: Build A Remove List

You can build out a remove list straight from the backlink audit tool once you have selected one or more links.


If you are going to attempt to remove these links, go ahead and move them to your ‘to remove’ list from the ‘Delete’ tab. This assumes you have been able to find an email address to send the removal request to. Otherwise, you will need to disavow the link. 

Also, users can use the Remove tab for change requests as well. An example would be asking someone to change a link from dofollow to nofollow.

Step 2: Connect Your Email

Head to the ‘remove’ tab, and you will now be able to hook up your email account to the tool if you are using Gmail or a Microsoft email account. Once that is done, you will be able to send removal requests with one simple click. 

Simply click the add button next to ‘mailbox’ to connect your account. 


Step 3: Send A Removal Request

From here, it is simple and straightforward to send a removal request based upon the templates provided. Just click the ‘send’ button alongside the links on your remove list.


You will then be able to customize the template as needed, but it is usually good just to enter the email address for the domain and hit send.


Step 4: Monitor Removal Requests

The last step of removal is to monitor any responses which you receive — you can do this in the status column of the report. You will be able to see which stage of the process each link is at, allowing you to go back into the email tool to resend or follow up if your original email has either not been opened or hasn’t been replied to.

Anchor text example

Step 5: Export Your Removal List

You can explore your removal list as and when needed, allowing you to see the status of the link. If your removal attempts are unsuccessful, you will need to disavow these toxic links.

If you are running a routine link analysis, have been unsuccessful at removing toxic links, or are simply skipping that step to remedy an algorithmic filter that has been applied, you will need to disavow these links.

Below I will show you: 

A disavow file is a request for Google to ignore the links which you upload and ensure that they are not taken into account when analyzing your site’s ranking factors. It is a great way to handle toxic links.

Disavowing toxic links can help your site to recover from penalties or prevent them from happening in the first place. However, it is important that you use Google’s Disavow tool very carefully as doing so incorrectly can potentially harm your site’s performance. In fact, you will see the following warning before you use the tool:

disavow links warning

But how do you disavow spammy and unnatural links? 

Step 1: Upload Your Disavow File

Some things to keep in mind:

  • Uploading a new disavow file to the Google Disavow Tool will overwrite all previously uploaded files.
  • A user must always ensure that the file contains all previously disavowed links and not just the new ones.
  • After uploading your disavow file, you will have to wait up to 6 weeks before Google takes your file into account.

If you have previously submitted a disavow file for your domain, you can upload it to the tool straight onto the ‘disavow’ tab.

How to upload your disavow file

Ignore this step if you have never submitted a disavow file before or run the import to check.

Head back to the Backlink Audit and tick the links you want to disavow before clicking the ‘delete’ button and sending it to disavow.

It is as simple as that. It is almost always recommended that you disavow at the domain level, rather than URL level, as this handles sitewide links which can be problematic as well as any others which appear on the domain in the future.

Showing how to add links to your disavow list

You should now see these domains added to your disavow list:

adding domains to your disavow list

Step 3: Export Your Disavow File

Once you are happy that your disavow list is complete and that you have added all of the toxic links which you want to take action on, you need to export your disavow file. You will see a button in the top right to ‘Export to TXT.’


This will export your disavow file already prepared to upload to Google’s disavow tool, broken down into URLs and domains.

Step 4: Upload to Google

Head straight to Google’s Disavow Tool, making sure you are logged into Google Search Console.

Google’s Disavow Tool

Upload your .txt file, hit submit and you are all done. 

It is important that you are running backlink audits regularly as part of your everyday SEO activity. Not only can you spot issues caused by toxic links before they become an issue, but you will be in a better position to clean up any past mistakes. The SEMrush tool Backlink Audit conducts, by default, a bi-weekly profile re-check and sends updates.

With a great range of tools available to help you know your link profile inside out, and take action to remedy any problematic links, there is no reason to suffer negative actions. The impact toxic links can cause is huge, and the more you do to stop this happening, the better position you will be in for long-term growth.

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Author Photo
James is Managing Director of award-winning digital PR and SEO agency, Digitaloft, and has been involved in search marketing since the mid-2000s. He‘s a regular writer on topics including link building, content marketing and ecommerce, having previously contributed to the likes of Search Engine Journal.