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What is Spam Score and What is it Used for?

There are a number of factors that can jeopardize your website and its search rankings. One of the major concerns every professional should pay attention to is whether or not their website is riddled with ‘spam backlinks’. This is something that Moz’s Spam Score can help with.

Simply having a lot of backlinks is not the way to succeed when building your SEO strategy. More does not mean better. Too many spam backlinks can have disappointing consequences to your site:

  • Penalties by Google
  • Losses in search engine rankings
  • Getting deindexed (in severe cases)

To mitigate these outcomes, you need to be informed about how your site is viewed by search algorithms and take action to remedy any concerns. Fortunately, there is a helpful scoring metric known as a ‘Spam Score’.

This article will help you better understand this useful tool; how it assesses your site; how to use it to ensure the safety of your rankings and how you can combat a low Spam Score.

A Guide to Spam Score

Traffic light level of Spam Score, read means highly spammy subdomain

Spam Score is a metric introduced by Moz in 2015. Developed by the company’s Director of Data Science, Dr. Matt Peters, it indicates how spammy a subdomain may be perceived by Google.

One very important distinction is that Spam Score is not used in Google’s algorithms – it’s a metric developed by Moz. The score itself is mainly useful as an added signal in making better informed SEO decisions.

Upon its first release, Spam Score analysed a website against 17 spam signalling factors, coined by Moz as ‘spam flags’. As the tool evolved, Moz incorporated more spam signalling factors ‘flags’. There are now 27 ‘spam flags’, which we will explain in detail later.

The aggregate of these flags is represented by a single score that indicates the likeliness of a site being penalized by Google. The more flags a site accumulates, the higher the Spam Score, and the stronger the prediction that it will be perceived as spammy by Google.

These flags allow you to break down areas of concern but are meant to be taken as a whole: a single flag is not usually enough for concern. In fact, it is quite common for sites to have at least one or two flags.

The Importance of Spam Score for SEO

Spam Score is crucial because it provides you with two important pieces of information:

  • How spammy your own website’s subdomains can be perceived
  • How spammy the subdomains of links pointing to your website can be perceived

In terms of your link profile, it shows that simply having a lot of thoughtless (spammy) backlinks can actually do more harm than good.

In addition to all these things, the Spam Score provides you with a solid framework to figure out the quality and spamminess of a single page. This way you can easily avoid being penalized by Google.

Learning the Mechanics: How Does it Work?

Overall, understanding the mechanics behind Spam Score is pretty straightforward.

Spam Score itself only operates on a subdomain level rather than for full pages or root domains. The reason for this, according to Moz, is that most spam links seem to be associated with the subdomain level.

What this means is, even if someone does have a somewhat high Spam Score, it is only applicable to their subdomains. It does not mean their entire website is spammy.

Spam Score is only accessible through Moz's Link Explorer

As to how it works, each subdomain has a Spam Score and a number is added for every spam flag it finds.

These individual spam flags are then combined to output an ultimate Spam Score, which starts from 0 and ends at 17. Generally, the lower the Spam Score, the better. However, this is not always the case as we will see.

A Few Interesting Points about Spam Score

Surprisingly, every single website on the Internet has at least one spam flag, so there is no need to panic if your site has a few.

Having one flag doesn’t mean that search engines will automatically consider your site as spam (otherwise every page on the internet would be labeled as spam). It’s also important to note that this score is relevant to subdomains only – you should not freak out if you see a Spam Score from the get-go.

Considering that the Spam Score is cumulative, a website only begins to raise problematic signals when their spam flag count increases. In other words, the more spam flags a subdomain has, the higher the possibility it will be considered as spam.

Getting more flags show that a sight is highly correlated with being Spam, Spam Score based on these flags
More than 14 flags gives a 100% probability that a site would be considered as spam by Google

The table above is from Moz, where they pulled data from November 2014 for approximately 500,000 subdomains. As Moz says, the table shows “the relationship between the number of flags and percent of sites with those flags that we found Google had penalized or banned.

This is where we see how clever the tool is. Moz has done the groundwork, understanding and correlating different factors with evidence from Google’s own rankings.

Considerations When Looking at Spam Score

Since Spam Score only considers subdomains within pages analysed, you may be asking yourself – what exactly is a subdomain?

The image below can help you get a better idea of the three different types of domains:

URL containing all three types of domains, Spam Score is applied to a subdomain only
A URL that has all three domain types. Spam Score assesses the subdomain level of a site.

Since Spam Scores ultimately operate at the subdomain level, you should be aware that a page with a high-risk subdomain does not necessarily mean it is completely spam. In the same regard, a subdomain with low risk can also have several spammy pages.

It’s important to check both the subdomains and the individual pages before jumping to conclusions from a single score.

If your subdomain has a Spam Score of 8, it doesn’t guarantee that the site is real spam, while having a Spam Score of 2 doesn’t necessarily mean that the site is a really good one either.

Spam Score is Good, but it’s Not Everything

While Spam Score is a great metric to measure whether a link is spammy or not, it doesn’t provide a complete picture. It’s worth considering:

  • The number of external links from the page that links to yours
  • The top-level domain of the website that links to yours
  • Other scores like MozTrust, MozRank, etc.

It is important to note that none of the metrics from Moz are used in Google’s algorithm (including Spam Score). Moz has tried to intimate what spam signals Google’s secret sauce algorithm may be looking for. For SEO, it serves as an important metric that can help you make better-informed decisions.

The Signals of Spam Score

When Moz first created the Spam Score metric, it began using an aggregate of 17 ‘spam flags’ to indicate whether a site was spammy. Over the years, using machine learning and big data sets of penalized/banned domains, they now rely on a total of 27 different factors, which they now refer to as Spam Score Signals.

  1. Low MozTrust to MozRank Score
    MozTrust and MozRank scores are two of the most important metrics used by Moz to determine the trustworthiness of a website. If a website has a lower MozTrust score in comparison to its MozRank score, there is a high chance of it being spammy. They use a scoring scale between 1 and 10, with a higher score indicating a better chance the site is trustworthy. It is important to check these scores with Moz’s Link Explorer.

  2. Large Site with few links
    Any site that has a lot of pages, but very few links throughout indicates that the content of those pages have no real value in them. This tells search engines that these pages are not worth linking to, and thus considered spam.

  3. Low link diversity
    This flag indicates that the majority of inbound links are from a handful of domains. For example, if a site has 500 inbound links but only 5 linking domains, then it is generally considered to have low link diversity. In other words, if those 500 links came only from 5 sites, then this flag would be applicable.

  4. Ratio of dofollow vs nofollow links
    While it may not appear that important, you should pay attention to the ratio between dofollow vs nofollow links. If the number of inbound do-follow links of a site are much higher than no-follow links, it indicates the site may not be earning those links naturally.

  5. Minimal branded anchor texts in inbound links
    Today, simply making specific keywords as anchor texts is not going to do too much for your page ranking. We recommend a balanced ratio of different types of anchor texts to ensure your links are optimized well. Sites that are organically linked tend to have lots of links with branded anchor texts.

  6. Thin content
    After the release of Google’s BERT algorithm, websites need to step up their game in providing top-quality content. The search engine is making sure it helps users get the best results for their queries. Moreover, with so much content out there these days, visitors are also looking for something in-depth and reliable.

  7. Small site markup
    Site markup consists of things like JavaScript, CSS, and Schema. The actual purpose of a site markup is to enhance the experience of the user. Therefore, sites with little markup like basic HTML, poor structure, a heavy page with little formatting and low-quality graphical elements are clear signs of spam.

  8. Low number of internal links
    Websites that have a lot of valuable pages and content will be more likely to have internal links. In addition, internal links help users stay longer on a website, indicating a meaningful experience for a user. Sites that have a low number of internal links may be marked as spam.

  9. External links in navigation
    Often times, sites that are built for a user do not have external links on their navigation menus. If there are a lot of external links in those areas, it can often be mistaken that they are those places indicating pure advertising.

  10. No contact info
    Reputable sites always have contact information, no matter what type of site it is. This can be included in a header or menu, and visitors should always feel like they can correspond with the administrator.

  11. Low number of pages
    In general, sites with too few pages are considered spam. You don’t have to create hundreds of pages, but ensuring that each page is filled with meaningful, valuable content is important.

  12. Length of domain name
    There was a time when people used to put their whole keyword inside the domain. While it is certainly okay to do this, it is not recommended if the keywords are long tail, and it causes the domain name to be too long. People want domain names that are short, simple, and straightforward, otherwise, it can be considered spammy. The maximum limit of characters for domains to be considered spammy is 63 characters, you definitely should not choose a name that comes close to this number. According to a study by Gaebler back in 2009, it was reported that of the most popular 1 million websites ranked by Alexa, the average domain name length was about 10 characters, with the top 50 websites possessing 6 characters. These stats can give you an idea of what range to stay within.

  13. Domain names with numbers
    While it may feel unique and somewhat cool, a domain name that includes numbers is not something that search engines like Google look highly on. It is better to avoid the risk of being considered spammy and keep your domain name limited to the English alphabet.

  14. Domain names with hyphens
    Not only is it more difficult for visitors to type out your URL, but spammy sites tend to be more likely to use multiple hyphens.

  15. Top-level domain (TLD) correlated with spam domains
    Any top-level domains that have a reputation for creating spam sites can send a red flag and may indicate a potentially spammy site.

  16. No Google Font API
    Domains that do not use special fonts such as the Google Font API, are perceived to be similar to other spam sites.

  17. Lacking Google Tag Manager
    Oftentimes, spam sites tend not to have Google Tag Manager on them. This is important when setting up a website, as it is a free tool offered by Google that helps you manage marketing tags. It helps to future-proof your site and improves security and flexibility.

  18. Lacking Doubleclick
    Similar to the above, sites without the Doubleclick ad tag tend to be considered spam sites. This is Google’s way of managing online advertising, as it helps you control time and location where ads appear.

  19. Lack of LinkedIn link
    Sites that have an associated LinkedIn link were far from being tied to spam. Therefore, on the flip side, sites lacking a LinkedIn page have a higher likeliness to be correlated with spam.

  20. SSL Certified
    If a site is HTTPS, it means that it has been SSL certified. This certification refers to data files that act as a padlock on the web, allowing secure connections from the server to a browser. It is used to keep sensitive information encrypted, indicating a safe, secure website.

Browsers warn user about navigating to site without https web address, sites without are more likely to be Spammy
A site without an SSL certificate will warn visitors in their browser
  1. Too many meta keywords
    Web pages that possess too many meta keyword tags tend to be tied closer to spam than those that do not, so a site that possesses a lot of them could be marked as spammy.

  2. Meta keywords that are too long or too short
    If a site does choose to have meta keywords, those that are either too long or too short tend to be correlated with spam.

  3. Long meta descriptions
    While adding meta descriptions is encouraged for better SEO, Google generally cuts them off at 155-160 characters. Spammy sites often take this overboard, by writing out long meta descriptions. We recommend keeping them limited to 50-160.

  4. Non-local rel=canonical tags
    A rel=canonical tag helps search engines know that the specified URL is the master version of the page. Sites that use a non-local rel=canonical tag pointing to an external URL are often associated with being spammy.

  5. Facebook Pixel
    According to Moz’s research, sites that have Facebook Pixel – a code added to your website to measure user behavior and actions – are almost never considered spammy. Those that don’t have more likeliness to be marked as spam.

  6. Webspam topic words
    Sites that are considered spam tend to be sprinkled with words that are closely associated with webspam topics like adult content, casino sites, gaming, etc. It is best to avoid the use of these specific words.

  7. Lack of browser icon
    High-quality websites that are well-optimized tends to have favicons – the small website icon at the top of your browser tab. Spam sites rarely use them.

Sites not using a favicon are correlated with being Spammy and therefore incur a higher Spam Score
A site favicon can be found in the browser tab and is usually similarly branded

How to Use the Spam Score?

Now that you’ve come this far and are well aware of what a Spam Score is, the question remains: what do you do with this score?

Spammy subdomain

With Spam Score, you can determine whether your subdomain is spammy or not, and if it is, you should immediately take action to identify and rectify any spam signals. Having a spammy subdomain may deter your site from being optimally ranked on search engines.

Quality backlinks

You can also determine whether the backlinks pointing to your website are of high quality or not. Amateurs in SEO immediately presume that having more backlinks is better, but as the old adage goes ‘quality beats quantity.’ You want to ensure that sites linking to yours are authority pages that search engines deem as trustworthy.

Using a Disavow Tool

Sometimes, you may have no control over whether a spammy site backlinks to you. In some circumstances, this can negatively impact your rankings. For those who do not have control over spammy links, you can use Google’s Disavow Tool.

The tool tells Google to disregard certain links as specified by you, which can help prevent your site from being penalized.

Googles Disavow tool warns users before committing their disavow files as this can dramatically affect SEO
Google's Disavow tool's disclaimer

While this is a very useful tool to improve your rankings, we do not recommend using it whenever and however you wish. Google itself suggests to only use the tool when your site has a lot of low-quality backlinks and you are very certain that they are causing problems. We recommend reading this article from Neil Patel if you decide to disavow any links. Before you decide to use Google’s Disavow Tool, first try to remove the link yourself by sending an email to the source. This action should be done with care, as it can be seen as malicious and does not come with a good reputation, but there are always ways to go about it politely.

Detailed Considerations of a Spammy Site

Even if a Spam Score is great, it is not everything. There are a ton of other indicators to denote that a website is spammy. To ensure the utmost safety of your website, it is always better to go deeper into your research, and look at the following:

‘Thin’ Content

While it may be difficult to determine the exact quality of content, and there are no specific tools that indicate this, it is best practice to create content that has depth.

In general, high quality content is longer – greater than 1500 words – and contain a lot of images, while also being written in a concise, easily-readable way. Using a lot of visual elements like images, infographics, videos, etc. can help beef up your content, making it more valuable.

Google values high-quality content and detests any content that does not contain any depth. Not only do they not create any value for users, it prevents engagement. Considering Google tries to provide searchers with the best results, it makes sense that it prioritizes pages with in-depth content.

Excessive External Links

One way that many websites look to get backlinks is by listing themselves on directories. While there are a handful of trustworthy directories out there, many of them are flooded with an abundance of external links that search engines likely deem as not valuable. This is not a good sign.

Websites like Wikipedia, however, are excluded from pages that consist of a lot of external links but signal danger, as every single link on Wikipedia has its own unique purpose. As a fully informational site with millions of well curated pages, external links on Wikipedia provide real value to readers.

Generally speaking, besides informational sites and publications that hold some weight to them, it’s recommended to stay away from overloaded sites with more than 100 external links per page.

Pages Loaded with Exact-Match Keywords

There was a time when people over-optimized their pages with exact-match keyword and received results immediately. However, those days are long gone. These days, Google’s algorithms will carefully examine whether the content is relevant to the keywords used, and determines if it is beneficial to the reader.

Avoid Specific TLDs

While we did mention that subdomains are where Spam Scores are taken into consideration, looking at top-level domains can help to see whether your website may be seen as potential spam.

Any website that is based in the USA that has a foreign TLD runs the risk of being suspicious to search engines. With so many options for domain names these days, it might seem interesting to choose a TLD that is unique and different from the typical .com or .net. However, we recommend keeping it to the standard, because that is what works.

The following TLD’s are risky to use:

  • .date
  • .men
  • .organic
  • .work
  • .tk
  • .loan
  • .ml
  • .ga
  • .cf
  • .gq


Spam Score is a simple and straightforward concept, but one that a lot of professionals may look past in their SEO strategy. This is unfortunate, as even the slightest mishap can cause problems in your overall ranking. With the knowledge from this article, we hope you will be able to better make use of Spam Scores and improve your overall SEO strategy.

If you require advice on lowering the Spam Score of your website or inbound links, please contact us to schedule a free consultation.

Aaron Chi

Aaron Chi is a digital marketer that has a deep passion for human behavior. As a lover of words and focus in content marketing, he dives deep into breaking down the science behind SEO and relating that to data analytics, and eventually artificial intelligence.

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