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Introduction to Back Links

A Guide to Back Links



Back Links

Backlinks are arguably the most important component in Google’s ranking algorithm, because back links deliver all of the authority that a website has.

What are Back Links?

Anyone who has been on the internet has clicked a link (formally known as a hyperlink) at some point. When you click a link it typically opens a webpage in the current tab or a new tab on your internet browser.

Any link that points to another domain is a called a ‘backlink’ or ‘back link’. When a website links to your website, the link is referred to as a ‘back link’ for the site being linked to.

Why Are Back Links Important?

Each link passes through authority from the site containing the link to the site being linked to; and this authority is one of the two most significant top-level ranking factors… (Relevancy being the other).

Used by Search Engines

Google and search engines in general consider a back link to be a ‘promotion’ or ‘recommendation’ and so broadly speaking the more recommendations that your site has the most authority it will have…


The more authority a site has, the more likely it is to rank for its target keywords. Typically, the site seen by a search engine as being a combination of the most relevant and authoritative will be ranked highest for any particular search term.

Referral Traffic

Other than the benefits that links provide to the organic visibility and performance of your site, back links also act as a gateway to your site for people who click those links. This results in what is commonly referred to as ‘referral traffic’, which in itself is a benefit that cannot be ignored.

Google Penalty

But before you head off and start trying to acquire back links there are also a lot of other reasons that make back links very important, that you should be made aware of first!

Back links are not only a powerful ranking factor; they are also a source of potential problems for your site… From our experience the majority of website suffering a penalty from Google have incurred this from having a ‘bad’ back link profile.

Link building / acquisition tactics that contravene Google’s guidelines can and very often do result in being slapped with a penalty from Google. We cover in this guide all of the areas that should be looked at in your link profile to both avoid a penalty from Google and organically improve a website’s authority.

Some History of Backlinks

As you may already be aware, Google update their algorithm constantly with minor tweaks, major overhauls, testing and such like… Consequently, in the past, especially the further back you look, you will find all kind of link building strategies and tactic that are now either ineffective or downright dangerous.

A lot of businesses have paid the price for using these kind of strategies… Google set the rules (guidelines) early on and although they are updated incrementally, they haven’t changed drastically in many years. What has changed significantly and regularly is Google’s ability to detect guideline violations and consequently enforce them.

At the time of writing this guide, Google are highly adept at detecting a lot of potential violations of their guidelines. They are also quick to penalise websites and web pages when they detect such violations. In fact, a lot of Google’s biggest and most significant algorithm changes have centred around back links and link profiles.

Components of Back Links

In this section we look at each component of a single back link.

Anchor Text

Anchor text is the visible text used (in a text link) to link to a target page. For example:

<a href=””>Home Page</a>

In the above code you see “Home Page” this is the anchor text for that link and this is what will be visible. The styling of links varies between sites, but typically they are underlined either permanently or on mouse-over (when the mouse cursor moves over the link).

What is a Text Link

In the example above, "Jon Wye's Custom Designed Belts" would be the anchor text of this link.

Types of Anchor Text

We cover this and the importance of having natural keyword usage within anchor text in more detail in the section on ‘anchor text ratios’. For now, we will suffice to say that there are various types of anchor text that can be used in back links:

  • Keywords: If you have performed some keyword research and have a defined list of target keywords, you can use a target keyword within the anchor text of a link.
  • Brand: The use of branded anchor text is very common and can include a brand name or variations of that.
  • URL: Using the whole or partial URL of the page being linked to within the anchor text is also legitimate and commonplace.
  • Instructional: Terms like; click here, more info, learn more, etc. are also common and although they provide little value from an SEO perspective, they are a useful technique for reasons that will become apparent as you progress through this guide.
  • Random & or Unrelated: Random or unrelated anchor text typically should be avoided. Using terms that are either not relevant to the landing page or are completely random (such as alphanumerical character strings) should also be avoided.

Importance of Anchor Text

Anchor text is a vital component or mechanism for associating relevance between the target keyword/s being used as anchor text and the page being linked to. Using branded and keyword rich anchor text is a great way to create relevance to your target keywords.

As well as being a valuable component of SEO, useful anchor text will help a user to understand what the link is likely pointing to.

First Link / First Anchor Text

We discuss this in more depth in our guide to internal linking, but it is worth noting that Google typically only looks at and counts the first link (if multiple links to the same page exists) on a page.

However, it is possible to ‘force’ Google to count multiple links to the same page, if different anchor text is used; this is achieved by using hashtags linking to anchors on the target page.

Linking Domain

Any domain linking to your site can be referred to as a ‘linking domain’ and there are many components that you will want to be aware of when assessing a link profile. When we are talking about ‘linking domains’ (plural) we are talking about the number of domains that link to a site, rather than the number of backlinks, as a single domain can link more than once to a site.


We have mentioned the relevance of anchor text previously, but this is not the only type of relevance that needs to be considered. The major components are as follows:

  • Domain relevance: Ideally any domain linking to yours should be broadly relevant to your business or website. For example, if your website provides leads to banks for banking products, receiving links from financial sites, banking sites, financial news, etc. would be a relevant source of links.
  • Sub-section relevance: Some sites range across multiple verticals and industries but have sub-sections specific to certain niches… For example, if you sell travel insurance, you might look for travel sites that have a sub-section covering travel tips… This would be a great place to try an acquire a link.
  • Page relevance: Ultimately and at the very least, you will need the specific web page linking to your site to be broadly relevant in terms of the content on that page.
  • Contextual relevance: If the link is nested in relevant content on a page, even if the rest of the page or site bears no relevance, this is still valuable. The ideal link will site in content that is contextually relevant to the content on the page being linked to. This allows for optimal amounts of relevance to be gained vs having the link outside of that contextual position.

The more relevant the page (and surrounding content) linking to your website, the more effective the link is at creating relevance between your site and your target keywords.


Acquiring links from an irrelevant page, for example; a page with content targeted around fashion, linking to a page that sells water pumps would be seem suspicious to any search engine. There are always exceptions and scenarios where this could be seen as legitimate for one reason or another. For example, some businesses are owned by umbrella companies or have affiliates, partners, etc. and hence these often interlink.


Authority reflects the ability of a domain or page on that domain to rank for target keywords, but independent of any specific keyword. If you are in the process of building links to your site, you will want to know the authority of any particular site from which you are potentially to acquire a link.

Measuring authority is another matter altogether and since Google have officially removed PageRank from the public sphere as Search Engine Land mention in this article from March 2016… It has become much harder for people to know how much authority a site has. So below we have briefly described some measures of authority that are most commonly used among the SEO world.

As with all authority metrics, these are based on algorithms that look at a range of indicators and metrics to derive a number (typically between 1-10 or 1-100) where the higher the number the better.


Wikipedia describes PageRank as the following:

“PageRank is an algorithm used by Google Search to rank websites in their search engine results. PageRank was named after Larry Page, one of the founders of Google. PageRank is a way of measuring the importance of website pages.”

Source: Wikipedia

As mentioned, although Google still use PageRank, this is no longer available to the public… Even when it was available it was updated irregularly before eventually being phased out.

Domain Authority (DA)

Moz use 40 signals to create a (100-point scale; 1-100) score that predicts how well a website will rank on search engines. It is also important to know that the score works along a logarithmic scale… A logarithmic scale is a non-linear scale:

Image result for logarithmic scale

Image Source:

Essentially on a logarithmic scale each point is a magnitude higher than the previous mark / point. What this means in real terms for your website is that, improving your DA from 10-20 is a lot easier than improving from 90-100.

This is a great metric to use if comparing your website to that of competitors and for tracking DA over time, but like any metric it will not mean much in isolation. DA can also be a strong indicator of good domains from which to acquire links.

Source: Moz

Page Authority (PA)

“Page Authority is a score (on a 100-point scale) developed by Moz that predicts how well a specific page will rank on search engines. It is based off data from the Mozscape web index and includes link counts, MozRank, MozTrust, and dozens of other factors.”

Source: Moz

This metric provides a more granular analysis at page level of a site and can be another good indicator of how valuable a link from this page is.


“MozRank represents a link popularity score. It reflects the importance of any given web page on the Internet. Pages earn MozRank by the number and quality of other pages that link to them. The higher the quality of the incoming links, the higher the MozRank.”

Source: Moz

This metric provides a similar granular analysis at page level to that of Page Authority (PA) but specifically refers to the authority received from back links.


There are many metric (typically the registered trademarked properties of companies) that SEOs use, but thy all refer to the ontological object of ‘trust’ or ‘trustworthiness’. On of Google’s questions when they look at a site is ‘is this site trustworthy?’, because they don’t want to send their users to dodgy parts of the web.

Sites can be untrustworthy for a number of reasons, such as having malicious malware, spyware, viruses. Trust is not limited to just those trying to be malicious, it also considers a wide range of factors:

  • Sites selling Viagra
  • Sites selling illegal goods
  • Sites that are super ad heavy
  • Sites that hide content or break Google guidelines
  • Sites with auto-generated content
  • Very badly written content
  • Sites with constant popups
  • Spam sites

Even this list is by no means exhaustive… Sites can also be considered untrustworthy because of the backlinks they have, having a lot of backlinks from sites that Google doesn’t trust is also not very good!

Untrustworthy sites are more likely to link to and be linked to from other untrustworthy sites, be careful where you link to and where you get your links from.

Whether its Majestic’s Trust Flow or Moz’s MozTrust, these algorithmically created scores represent and attempt to evaluate how trustworthy websites and web pages are. Below we describe the top Trust metrics used in SEO:


This is a Trademarked metric of Moz, they use this to assess and analyse the trustworthiness of a site or page, this is how they describe it:

“MozTrust is Moz's global link trust score. It is similar to MozRank, but rather than measuring link popularity, it measures link trust. Receiving links from sources with inherent trust—such as the homepages of major university websites or certain government web pages—is a strong trust endorsement.”

Source: Moz


“TrustRank is a link analysis technique described in the paper Combating Web Spam with TrustRank by researchers Zoltan Gyongyi and Hector Garcia-Molina of Stanford University and Jan Pedersen of Yahoo!. The technique is used for semi-automatic separation of useful webpages from spam.”

Source: Wikipedia

You can read the paper that these guys wrote here.

Trust Flow

Trust Flow (a registered trademark of Majestic) represents a ‘quality’ metric on a logarithmic scale of 0 to 100, with 100 being the highest.

This metric is designed to provide insight into how trustworthy a site or page is, based on the Trust Flow of the sites and pages linking to it.

See the section on ‘Flow Metrics’ for more information on this topic.

Follow Vs. Nofollow

Follow: These allow PageRank to flow through to the target page. This is the default for links and doesn’t require any modification; when adding a link, unless specified otherwise, it will be a ‘follow’ link. Below is an example of a standard HTML link to the home page of would look:

<a href=””>Home Page</a> - This is the code.

Home Page = This is how it would appear on the page.

Nofollow: The do not allow PageRank to flow through to the target page. To make a link ‘nofollow’, you will need to add some code:

<a href=”” rel="nofollow">Home Page</a> - This is the code.

Home Page = This is how it would appear on the page (note that the nofollow tag does not change the appearance of the link, so to see if it is nofollow you will need to analyse the code).

Nofollow links can be used to limit PageRank flow to pages that you do not need to deliver PageRank to and are often used to prevent authority from leaving a site.

Summary: You ideally want the vast majority of your back links to be ‘follow’ links, as this will allow authority to pass to your site through the link. That said it is healthy and natural to have a portion of nofollow links pointing to your site; there is no golden number for this however.

Social Links and Signals

Google said in 2010 that social signals were part of their ranking algorithm but later in 2015 said that they were not… Leaving most people wondering if they are and Google simply don’t want gaming to ruin it. There is at least a correlation between domain authority and social media links. Certainly being present on social media and with a legitimate following won’t harm your efforts.

In addition to any SEO value they may provide in the form of backlinks, legitimacy and algorithm ranking factors, social media provides a host of other advantages to your online marketing strategy.

Social media is also, for a lot of businesses, a great channel for seeding and promoting your content, reinforcing your brand and growing your audience. Read more about social media in our guide to social media.

Text Links

Text links are the most common kind of back link type for most sites, these are the links you are most familiar with, such as those that punctuate the content on this page. These pass on optimal authority and relevance and are the preferred type of link to have pointing to your site.

Image Links

If an image is used as a link to another page, the Alt Tag will be used in place of anchor text for delivering relevance to the target page. This won’t deliver as much relevance as a text link, but will provide no relevance at all if the alt attribute isn’t optimised for the target page’s target keyword. For more information on internal linking, please follow the link.

In summary, if you can optimise the image backlinks then follow the instructions below:

  • Use descriptive language
  • Do not keyword stuff
  • Use keywords where relevant
  • Do not include use alt tags on template images (such as sidebar, header, etc)
  • Include relevant information such as product name, model number, serial number, etc if the image is of a product
  • Optimise Alt tags for keywords of the target page if being used as a link

Bad Links

There are a range of factors that can contribute to making a bad link, these are always changing and being added to, so this is not an exhaustive list.

Buying links

Buying links is a massive ‘no no’ for anyone who would like to avoid a penalty from Google. There are a number of ways in which you can illegitimately buy links such as paying directly for a link or paying for sponsored guest blog post on a site that does not label the post as ‘sponsored’.

Paying an SEO agency to do link building does not fall into this category. If you would like to know more about the pitfalls of buying links, please follow the link.

Bad Sites

Links from sites that meet any of the following criteria are not places you would want to get a link from:

  • Sites that violate Google’s guidelines
  • Gambling sites (unless you’re in the industry)
  • Sex / Adult sites (unless you’re in the industry)
  • Sites with very poor content
  • Sites that are just link repositories / link directories
  • Spammy sites
  • Sites with too many ads
  • Sites that contain malicious software
  • Racist or abusive sites
  • Sites that sell or engage in illegal activities

Bad Anchor Text

Anchor Text that includes any of the following is not great for trust:

  • Viagra
  • Selling drugs
  • Selling illegal drugs
  • Keyword stuffing
  • Adult terms

Back Link Profile

We have discussed the components of an individual link, in this section we discuss the aggregated components of all a website’s links, which we often refer to as a ‘link profile’.

Link Neighbourhood

The link neighbourhood is an analogy to an actual neighbourhood, is your link profile largely made of trustworthy links? To extend this analogy; a house in a bad neighbourhood will be worth less than the same house in a good neighbourhood. The same is true for websites, if your ‘link neighbourhood’ or link profile, is largely made up of untrustworthy sites then your site will be in a bad link neighbourhood!

This is another way of assessing trust or quality in terms of your back-link profile

Anchor Text Ratios

Anchor Text RatiosAnchor Text Ratio Analysis

An anchor text ratio is the number of iterations of text, used in anchor text, as percentage of all the anchor text used to link to a page. For example, if a page is linked to 100 times throughout a website, you could use analyse the amount of times anchor text is used as a percentage, for example;

This is a much more important factor when considering back links to your website rather than internal links within the website. Due to the nature of template regions of a site containing links, it is likely that the most commonly used anchor text to your main pages will be that used in the main navigation.

Google is easily able to understand this and thus it is factored into the algorithm. It is only in extreme cases where thousands of internal links are created, in an unnatural way to a page all using identical anchor text where it could become an issue. Matt Cutts confirms this in a video from 2013.

That said it is always useful to vary the anchor text used to include variations of keywords, if you are running the risk of overusing a keyword in anchor text consider using generic anchor text on occasion such as “click here” or “for more information”.
Only in extreme cases are you likely to incur some kind of algorithmic penalty from Google as a result of unnatural anchor text usage, though it can happen.

Links to Referring Domains (Ratio)

This is represented as a number ratio (of the number of back links to the number of referring domains.

For example, if you have 500 back links coming from 100 domains, you would have a ratio of 5:1. What this means is that, in this example, we have an average of 5 links per domain.

Ideally you want this ratio to be as close to 1:1 as possible, although it’s unlikely to actually achieve this ratio when you have a large link profile. The reason for this is because each subsequent link gained after the first from any one domain will provide less and less value. Having a million links from a single domain does not provide a million times the value of one link.

Finding sites that have a very high number of links to your site can be an indicator of potential problems that can have a very strong negative impact on your site. So, this metric has standalone capacity as an indicator of areas you may want to take a close look at.

This ratio also acts a lens through which you see the number of backlinks the site has. For example, if we assume a small site that has 1,000 backlinks; and their closest competitors have just 300 on average. If our site were ranking lower than our competitors we might ask “why?”… This metric can reveal the answer, if we had a link ratio of 900:1 and our competitors were averaging 3:1, we would see why.

It’s always worth comparing this metric to that of your competitors to get an idea of whether your ratio is an outlier, better, worse, etc.

Flow Metrics

Flow Metrics are the trademark of Majestic, and they are used in a number of capacities to help describe, rate / score and assess the quality, relevance and authority of backlinks and sites.

These metrics can be used to analyse a single link or the aggregate of all links, groups of links, categories of links, etc. As such, these metrics are very useful when analysing or describing a back-link profile.

It is worth noting that these metrics are only available with membership to Majestic, and if you use another tool you will be using their metrics instead. We include this due to the ubiquitousness of Majestic within the SEO industry.
There are two Flow Metrics, which we describe below in more detail.

Trust Flow

Trust Flow (a registered trademark of Majestic) represents a ‘quality’ metric on a logarithmic scale of 0 to 100, with 100 being the highest.

This metric is designed to provide insight into how trustworthy a site or page is, based on the Trust Flow of the sites and pages linking to it.

Citation Flow

Citation Flow (a registered trademark of Majestic) represents a ‘power’ or ‘authority’ metric, and also uses logarithmic scale of 0 to 100, with 100 being the highest.

This metric is designed to provide insight into how influential a site or page is… This can be further used to see how influential a site or page is within a certain Majestic category.


This is discussed in more depth in our guides covering backlink analysis backlink profile analysis.

This is a technique for analysing the backlink profile of your site and those of your competitors, it’s easier to show you than to explain it, so… The table below shows two columns; the left-hand column has DA (Domain Authority) grouped into brackets of 10.

The right-hand column shows how many backlinks your site has for the corresponding bracket of DA. In the example data below, you can see that this site had 484 backlinks from domains with a DA of between 20 & 29.

Authority Distribution Table

The chart below shows the data in the table above, this makes it easier to see the distribution of backlinks based on their DA.

Authority Distribution Chart

This technique of ‘showing the distribution’, can be applied to any most the metrics that we discuss in the document, MozRank, Trust Flow, etc.

As mentioned we cover these more analytical techniques in more detail in other guides within the backlink analysis section of Raptor’s Off-Page SEO Knowledge Base.

Backlink Acquisition

There are a number of technique for acquiring backlinks, we have listed some of the below but for more information on this topic read more in our guide to back links. We cover the most common forms of link building and authority building briefly in this section. Each of these is a topic worthy of its own guide, so we only cover the basic principles or benefits of this activity here.

Guest Blogging

Although Matt Cutts publically stated that “you should stop using guest blogging for link building” this is still a popular tactic for link building for many businesses. More than just acquiring links, guest blogging provides a range of ancillary benefits. Placing content on other websites gets both your content and brand in-front of new relevant audiences.

This kind of activity can also provide social signals, often when a guest blog goes live, the host website will syndicate the post out through their social channels. We discuss social signals a little later in this guide.

Others Guest Blogging on Your Site

Getting other businesses or individuals to post content on your site can also lead to improvements in authority, especially when the writers produce high quality content or have material brand collateral.

When a company posts content on another site, they will typically syndicate this through their social channels; this can provide social signals, deliver traffic and create connections between your site and another relevant and authoritative site.


Collaborating with influential figures and businesses in your industry or related industries can help both parties. For example, if both you and another company produce videos for YouTube, collaborating on a video will often lead to increases in subscribers, views, thus driving brand awareness and traffic to your site.

Although not an easy technique to achieve results in, this can be a powerful tool for a business to help acquire new links and reach new audiences.

Link Bait

Link bait is a broad category of techniques that can vary from simply creating great content that people will naturally want to link to or share. This can be any type or medium of content; a good example of this would be ‘Infographics’ which are often share socially or reposted (with a link to the source) on other websites. The aim is to be any (one or combination of) the following while also being unique in either content or approach:

  • Useful
  • Informative
  • Funny / entertaining

But link bait can include more targeted approaches, such as deliberately mentioning people, businesses and institutions within a piece of content and then reaching out to them to let them know they have been mentioned. A particularly good review could inspire the company being reviewed to repost or share the review for example.

Social Media

As mentioned, social media can be a powerful tool for promoting your content, your products and services… But it can also be a channel for building social media links. Links from social can come about in many different ways such as people sharing your web pages through on page sharing buttons.


Finding where your brand has been mentioned online can provide a constant source of links, especially for bigger brands that get regular online mentions. It’s easy to get a website to link to you if they have already mentioned on their blog or in an article. For the most part you can simply request that the mention itself be turned into a link (branded anchor text link).

This is obviously only relevant to when mentions are positive or at least neutral, a negative mention should be dealt with in a different fashion.

Competitor Analysis

Replicating what successful competitors have done is a great way to get ideas for sources of back links. There are some links that you cannot replicate but there will be many that you can; using various tools you can get a complete picture of any website’s back link profile and you can categories and prioritise these in a spreadsheet.

Apps, Tools and Widgets

Providing apps, tools, widgets and other such things as embeddable content for websites is a kind of link bait but should really exist in its own category. This technique has been used for years and is still good today. For example, creating a calculator for mortgage repayments and allowing others to embed this onto their website (with a link back to yours) can enable you to organically generate back links.

A more advanced version of this might involve a partnership with another business where your webpages are shown on another website through iFrames or duplicating content (using canonical tags). For example, you may have products or services that appear on another website as a white labelled product. Partnerships are much harder to acquire and often involve contractual agreements, costs and regular collaborative work.

Good PR & Outreach

For businesses that have a PR person or a PR team, there is huge opportunity for the SEO person to work with them feeding into their daily activities. PR teams often get stories published in online news outlets or get mentions online, SEO can help optimise this by providing recommendations as to what anchor text to use or when to ask for a link.

Many of the techniques listed here could fall under the umbrella of ‘outreach’, which is a broad description of contacting website owners, businesses and individuals through email or phone. Outreach has become the backbone of link building for many SEO agencies, who often have a team of people acting much like telemarketers, calling people every day in attempts to get links, place content (apps, widgets, blog posts, etc), get guest posts, arrange collaborations, etc.

Raptor Backlink Tools

Our backlink analysis tools are a comprehensive suite of analysis techniques and APIs that we use to pull in your backlink data, analyse it and make recommendations. If you haven’t checked, it out yet, click the link to sign up for a free 30-day trial of our Backlink Tools.


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