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Link building is one of the most important aspects of SEO. Links play a key role in how search engines understand and trust your website, so without links any website will struggle to perform well in organic search.
Hence, it’s important to understand how link building works, and how you might be able to apply it to your website or business as part of your SEO strategy.
So let’s dig into the topic and first cover off some of the basics!
Link Building Basics
What is Link Building?
Link building is the practice of acquiring inbound links (also known as backlinks) from external websites to a specific webpage or website. Links are traditionally regarded as having to be created or built, hence the phrase link building.
Why is Link Building Important?
Link building is important because links are a critical component of how search engines rank websites. Search engines take into account links and link signals in scoring, so if you hope to rank a website in the organic search results, you will need to attract links to it.
Historically, search engines ranked their results primarily on the content of the pages. This changed significantly when Google entered the market, with their PageRank algorithm. PageRank is an algorithm used by Google to measure the value of a page based on the quantity and quality of inbound links. This change placed a great deal of importance on links in order to rank in the search results, an importance that remains to this day.
Link building is also important because it’s rare that a website will naturally attract links at scale without any effort or activity to do so. Hence, it’s best to try to encourage and provide compelling reasons for other websites to link to your own. Creating content or undertaking marketing activities that cause sites to want to link to your website is the key to link building today.
It can be useful to think of links as votes of confidence or external recommendations for your website. If your website has a lot of links, it’s likely to be regarded as more trusted by search engines than a website which has no links. If your website is more trusted by search engines, it will likely rank better in the search results, helping to drive more organic traffic.
Link quantity isn’t the only consideration, link quality is also important.
What is a High-Quality Link?
Link quality is a difficult and subjective metric to measure. There isn’t a single definitive metric which tells you if a link is of high or low quality, so a blended view of the following factors can help –
- Relevancy – having links from websites of a similar type can be positive quality indicator. For example, if you are trying to build links to a travel website, links from other travel websites are likely to be more relevant than links from websites of a completely unrelated topic.
- Context – understanding the reasoning and context behind a link can indicate quality. Think about the following:
- Why is site A linking to site B?
- Does the link seem natural or is it rather unexpected?
- Does the link look paid or sponsored in some way?
- Is the link part of an editorial story where it feels logical that site A would link to site B?
- Source – related to context, the precise source of a link can be a quality indicator. A link which is ‘in-body’ or ‘in-content’ is located within the main editorial content of a page. These links which read naturally and seem logically located to users could be regarded as higher quality than other links. An in-body link might be more valuable than a link located in a website sidebar or footer, which could be perceived as less natural or less useful for users. This consideration was reflected in 2016 when Google updated their Reasonable Surfer Model patent, placing more importance on how likely it is that a user might actually click on a link.
- Destination – the precise destination (the landing page URL) of a link matters when measuring quality. Considering the source and context of the link, a high-quality link destination will be one that naturally matches that original source and context. For example, if a news story about a company’s financial results is quoting the CEO of a company, it’s reasonable to expect that the story might link to a profile page of the CEO on the company website, or perhaps a news page on the company website where the original financial results have been published. By contrast, a link to a commercial service or product page in this example would seem unnatural and out of context to the original story.
- Trust or authority – as a general rule, links from websites which are regarded as more trusted and authoritative themselves, are likely be more valuable for SEO than links from low authority websites. For example, the BBC is a very trusted and respected organisation, so a link from one of their web pages is likely to be higher quality than a link from a niche blog which is poorly maintained and has little or no user engagement. Google’s patent update to PageRank in 2018 with the inclusion of ‘seed set’ sites meant that links closer in sequence to a trusted set of seeded sites might pass more SEO value than those further away.
- Scale – the amount of links a website has can be a factor in measuring quality. If a website has lots of links of a certain type, this can sometimes be an indicator of a pattern of link building, which might be less effective for SEO. Diversity is important, so all things being equal, a mixture of link types and sources is probably better for SEO than lots of similar links which create a clear pattern.
- Value to users – determining a link’s level of quality can often be measured simply by questioning if the link is useful and provides added value to the user. Higher-quality links generally make sense to users and reference other pages on the web, which provide further insight, context, and value from the original link source. If a user is likely to actually click on the link and visit the destination web page, then this can be considered as a positive quality indicator.
None of these individual factors should be taken in isolation as singular definitive measures of link quality. Instead they should be considered as part of a blended view.
How Important is Link Building?
Link building is a very important aspect of SEO today. Precisely how important is difficult to quantify.
Search engines consider hundreds of different signals within their algorithms for scoring; links are just one. Understandably search engines don’t comment publicly on these factors or on which are more or less important than others, and this will change over time in any case. But this doesn’t stop the SEO industry from speculating and from trying to reverse engineer the SEO performance of websites from a linking perspective.
There is a generally acceptance within the industry that links continue to be an important factor in SEO success. Search engines still need links to help in understanding which pages and websites deserve to rank better than others for particular search queries. Links help to do this. In fact, several years ago Matt Cutts (the head of web spam at Google at the time) stated that Google had tested a version of their algorithm which excluded links, but the subsequent quality of those search results was poor in comparison to the live results:
This indicates that links are likely always to play some role in SEO. It’s probable that the importance of links has lessened somewhat in recent years, as search engines have become more sophisticated and are now less reliant on links as a primary metric to inform them which pages are the best and most relevant results for users. But links continue to be an important factor, and at the very least give websites the platform to compete in the organic search results. Links are also a by-product of lots of other factors and activities relating to SEO; brand awareness, building relationships, content marketing, digital PR, driving referral traffic, and others.
It’s also important to consider link building as a single component of what’s required for SEO success. Building lots of links to a website which is poorly optimised from a technical perspective is just as ineffectual as having a flawless website which has no links. Websites need to be firing on all cylinders to see real and sustained success within the organic search channel.
What Types of Links Exist?
Not all links are created equal, so it’s important to understand the different types of links there are. To do this, visualising the anatomy of a link can be useful:
Above is the HTML of a typical hyperlink. This can be viewed in the HTML using a browser by right clicking on the web page and choosing ‘view page source’ to view the raw HTML, or ‘inspect’ element to view the rendered HTML.
Links That Pass SEO Value
By default, all links of the type visualised above are valuable for SEO and pass PageRank. Links that pass PageRank (sometimes known as ‘dofollow’ or ‘follow’ links) are the most valuable from an SEO perspective. These are sometimes known as links which pass link equity or ‘link juice’.
Nofollow links are links which have a rel=”nofollow” attribute applied to them within the HTML –
<a href=”https://www.screamingfrog.co.uk/” rel=”nofollow”>Anchor text example</a>
This attribute, where applied, tells search engines not to count the value of the link within scoring – it stops PageRank passing to the destination URL. Rel=”nofollow” was introduced to combat link spam and for websites to apply to any links which were paid or sponsored in some way. For example, if you purchase banner advertising on a website and the banner links back to your website, the value of that link shouldn’t really pass SEO value and be counted in scoring, as the link was paid for. Hence, the rel=”nofollow” attribute should be applied to the link to prevent it from passing SEO value.
In practice, rel=”nofollow” hasn’t always been used correctly. Some websites have mistakenly applied the attribute to links which are not paid or sponsored, and some sites even operate a blanket approach to all external links, making them all rel=”nofollow”.
This misuse of the attribute has contributed to more recent changes around rel=”nofollow” links. This 2019 blog post from Google explains the evolution of rel=”nofollow” and how the attribute is going to be treated moving forwards. It’s now treated as a hint by Google, so links with the attribute may now be considered in scoring rather than being ignored altogether. Google can now use these hints alongside many other signals it uses to determine the value and relevancy of rel=”nofollow” links.
UGC and Sponsored Links
At the same time as making its change in approach to rel=”nofollow” links in 2019, Google introduced two brand new link attributes: rel=”ugc” and rel=”sponsored”.
rel=”ugc” – UGC stands for User Generated Content, and the ugc attribute value is recommended for links within user generated content, such as comments and forum posts.
rel=”sponsored” – the sponsored attribute is recommended to identify links that were created as part of advertisements, sponsorships or other compensation agreements.
In theory, ‘follow’ links are still the best and most effective links from an SEO perspective, but links of all types can now be used in scoring to some extent. Furthermore, all links continue to drive referral traffic so are valuable from a general web marketing and brand awareness perspective.
What is Anchor Text?
Anchor text is the visible and clickable text in a hyperlink –
<a href=”https://www.screamingfrog.co.uk/”>Anchor Text</a>
Anchor text is important because it is one of key signals search engines use to determine the topic of a web page. The words used in link anchor text help to inform search engines what the linked page is about, and can have an impact on how well the page ranks for associated keywords.
For example, if the Screaming Frog link building services page has a lot of links with the anchor text ‘link building services’, that is likely to affect how it ranks for ‘link building services’ (and variants) in Google. Anchor text of this type is known as ‘keyword heavy anchor text’, ‘commercial anchor text’ or ‘exact match anchor text’. In theory, based on the anchor text and link recommendations, Google will see the page as being highly relevant to the keyword, so should rank the page higher.
However, there are caveats and limits to this. Over optimising anchor text can sometimes have a negative effect on rankings if search engines perceive your link building to be unnatural and intended to manipulate rankings. Excessive keyword heavy anchor text links are one of the clearest signals to search engines of over optimisation, which at best can be ineffectual, or at worst result in penalisation. You can read more on link schemes and penalisation by clicking the links.
Anchor text should be natural and relevant to the content and topic of the linked page. It is fine or even advantageous to have some keyword heavy anchor text links, but being excessive in this regard is not generally recommended. The more keyword heavy anchor text links you have, particularly in relation to your wider anchor text profile as a percentage, the greater risk of penalisation.
A natural anchor text profile contains a healthy mixture of keyword heavy anchor text (e.g. ‘link building services’), partial match anchor text (e.g. ‘Screaming Frog are link building specialists’), brand anchor text (e.g. ‘Screaming Frog Ltd’), and noise anchor text (e.g. ‘click here’).
What is Outreach?
Outreach is the activity which drives a lot of link building work — it is the practise of contacting and reaching out to relevant external websites you want to get links from.
In most cases links aren’t easily built without going out and contacting external websites to tell them about your website and content. They need to be approached and told about your content, why it’s relevant to them, and what value they might get by linking to it. This activity is known as outreach.
What Types of Link Building Exist?
Link building can be segmented into three distinct types: white hat, black hat, and grey hat. These terms have been coined by the SEO industry to categorise various link building strategies and activities.
White Hat Link Building
White hat link building is a term to describe link building which is considered natural, ethical, and compliant with Google’s webmaster guidelines. Undertaking normal marketing and brand awareness activities which naturally earn links as a by-product is considered as ‘white hat’. This type of activity is generally regarded as powerful and effective in the long term, though it can be challenging to scale and will often require long term investment. White hat link building can be the best way of building links from highly trusted and relevant websites, resulting in the high-quality links outlined earlier in this guide.
Some common white hat link building strategies include:
- Content marketing
- Digital PR
- Broken link building
- Unlinked brand mentions / link reclamation
- Resource link building
We cover link building strategies in more detail later in this guide.
Black Hat Link Building
Black hat link building is a term for aggressive link building which violates Google’s webmaster guidelines and is unnatural with the sole intention of manipulating search rankings. Activities which are classed as being part of link schemes are all black hat, and carry an inherent level of risk. Sites found to be participating in link schemes risk penalisation by search engines.
Some common black hat link building strategies include:
- Paid links
- PBN’s (private blog networks)
- Large scale articles or guest posts
- Pure spam (hacked pages, link insertion, comment spam)
- Template or footer link building
Black hat link building is still a fairly common practice as it’s often highly scalable, fast, and measurable from an ROI perspective. Utilising a PBN for example, will have a clear cost implication and can deliver immediate links at a large scale – something that white hat link building rarely can. However, the impact of those links is not guaranteed, and they carry the aforementioned risks too.
There is a perception by some in the SEO industry that black hat linking strategies are both highly effective (at least in the short term) and also necessary to compete within highly competitive niches. For some, they are worth the risk or at least useful as a component of a wider link building strategy.
At Screaming Frog we do not endorse or engage in any black hat link building activity.
Grey Hat Link Building
Grey hat link building is a term for link building which falls somewhere between white and black hat link building. It’s a subjective term which is open for interpretation and debate, but is generally considered to be link building activities which are more scalable than most white hat link building, but perhaps not as clearly manipulative and risky as some black hat link building. Grey hat link building will carry more risk than white hat link building, but can be effective in building links at scale.
Some common grey hat link building strategies include:
- Guest posting
- Product reviews and giveaways
- Reciprocal / link exchange
Depending on your perspective, most, if not all, of the above grey hat link building strategies could be considered as black hat. If implemented excessively and if your website is largely reliant on them, they carry the same risks as most black hat links.
This is because link spam is often detected by clear patterns, so if you build a lot of links of a specific type, which have a clear footprint either from the anchor text, link destination or link source, there is a greater chance this will noticed by search engines. If it is, there is a risk that your links will be ignored, or you might even face penalisation.
How Do I Build Links?
There are many ways to build links, and the best way that you can build links for your website will depend on lots of factors. To give you some ideas on the various options, let’s look in more detail at some common link building strategies.
Link Building Strategies
There are lots of different link building activities and strategies you can implement. Below are a number of the most common to get you started.
White Hat Link Building Strategies
- Content marketing – creating a piece of content with the intention of outreaching it to relevant media and external websites, to encourage them to link to it. The format of the content can be anything: video, podcast, blog post, news article, image, infographic, interactive tool etc., so long as it’s relevant to the sites outreached to and their audience. Ensuring the content is in the best format to be useful, engaging, original, and tells a clear story, is a recipe for the most effective content marketing.
- Digital PR – public relations with an online focus combines the best of traditional offline PR with link building and SEO benefit. There are proactive digital PR activities such as press release outreach, thought leadership, and business profiling. There are also reactive activities such as responding to media requests and providing expert comments on newsworthy topics. Digital PR can be very effective in attracting links from high-value media websites.
- Broken link building – finding instances of relevant external pages linking to broken pages (404 status pages) is an effective and scalable link building strategy.
- This can be 404 pages on your own website, whereby you have external links to the 404 page which could be 301 redirected to the next most relevant page on your site (thus retaining the link equity from the links to that page).
- It can also be 404 pages on similar/competitor websites – this is where you find instances of relevant external websites linking to similar/competitor pages which result in a 404 error. You can contact those external websites to alert them that they are linking to a broken page, and simultaneously ask them to consider linking to your very similar page.
- Unlinked brand mentions / link reclamation – finding instances where your brand are mentioned but not linked to can be an effective way of building links. This typically works best within news and media if stories are being written which reference your brand but without a hyperlink. By simply following up with the journalist or publication to ask for a hyperlink, this can result in fast, relevant, and valuable links.
- Targeted resource link building – there are many pages across the web which link to a range of useful and relevant resources for users. For example if you’re looking to build links to a travel tour operator website, there are many travel blogs and websites that link to commercial travel tour operator websites of this type. You can find these opportunities in a number of ways, for instance by utilising advanced search operators in Google like this. That example finds instances of travel websites that have pages which include ‘links’ or ‘resources’ in the URL, which are likely to be resource link building opportunities –
Black Hat Link Building Strategies
At Screaming Frog we do not endorse or engage in any black hat link building activity.
- Paid links – a catch all term for links which are paid for, which is against Google’s guidelines. If a link is only being given in exchange for money, it’s classed as a paid link. Most of the subsequent black hat link building strategies are a specific type of paid link.
- PBNs (private blog networks) – networks of websites which form a structure with the purpose of manipulating PageRank. The websites within the network cross-link in ways to build link equity, which can then be used to power a desired website by linking to it, resulting in higher SEO rankings. Links from PBNs are paid for or rented for an agreed period of time.
- Large scale articles or guest posts – articles or blog posts created at great scale, at low quality and with the sole intention of building lots of links. Sometimes known as ‘article spam’ or ‘article spinning’, this type of activity is often utilised in conjunction with PBNs, allowing for often many hundreds or thousands of low-quality articles to be created and containing links.
- Pure spam – link building can sometimes take a particularly malicious form, in the way of activity regarded as pure spam. Instances such as when a website’s pages are hacked and links are inserted without their knowledge, or where spam comments are being left with hyperlinks contained, are very risky and potentially damaging. This type of activity is most common in very competitive industries such as pharma or adult websites.
- Template or footer link building – website templates and footers can be built in such a way where they include hyperlinks. If these templates are then widely used and the links aren’t removed (they can even be hidden to users in some cases), they build links at a large scale. This is sometimes seen in the web design or website template industries themselves, as a scalable way to build links using the assets or websites they create.
Grey Hat Link Building Strategies
As mentioned earlier in this guide, many of the following grey hat link building strategies could be considered as black hat by some. Depending on their implementation and scale, they can carry greater or lesser risks.
- Guest posting – writing content which contains a link (or multiple links) to be guest posted on an external website is a common link building strategy. If done at a large scale, at low quality and with heavy anchor text links, this is likely to be considered black hat by search engines, risking penalisation. If you are contributing relevant and useful articles to external websites where your target audience are likely to be, at a sensible scale, this can still be a smart marketing activity in general, as well as for SEO.
- Product reviews and giveaways – offering products or services for free or to giveaway to readers in exchange for coverage and links, is strictly speaking against Google’s guidelines. Doing so at great scale and making links the core objective, is not recommended, but influencer marketing done sensibly is still worth considering if right for your brand.
- Directories – across the web there are many business directory websites. They segment businesses into categories, much in the way that something like the Yellow Pages did in print in the past. Directories have been somewhat abused by SEO in the past, as a fast and easy way to build links – you simply submit your website to a directory (sometimes for free, sometimes for a fee) and it appears in a relevant category with a link. As a result, many spammy business directories now exist purely to generate links, and most are low quality and provide no tangible SEO value. However, there are a handful of valuable directories which can be worth submitting to. These will differ depending on your business, but will generally be high value niche or local directories which users still utilise for recommendations.
- Widgets – creating widgets for other websites to embed and use on their own website has traditionally been a popular link building strategy. Widgets such as visitor stat counters or widgets to show off customer reviews are quite common, but can sometimes be abused for SEO benefit. If the widgets contain keyword heavy anchor text and if they are used on many websites at huge scale, this risks creating a clear pattern of links intended to manipulate the search results. On a smaller scale and when avoiding keyword heavy anchor text, this kind of link building can be considered less risky.
- Reciprocal / link exchange – where site A agrees to link to site B, only in exchange for a reciprocal link. There are plenty of cases where reciprocal links are fine and totally expected, but understandably search engines are not keen on this type of activity at great scale and when done purely to manipulate the search results. Like all grey hat link building strategies, if done at scale they are likely to risk penalisation.
Common Link Building Questions
We’ve covered some of the basics and key strategies around link building, so let’s now dig into some common questions or considerations around the topic.
What Are the Best Link Building Tools?
There are many different types of link building tools, often at varying costs and levels of functionality. The best tools for you will depend on your needs.
Link building tools can be split into two distinct categories – tools which help to undertake and scale link building (or media database / outreach management tools), and tools which measure link building, link analysis, and give competitor insight.
Examples of tools which can help to undertake and scale link building include:
Examples of tools which can help measure link building, undertake link analysis, and give competitor insight include:
There are lots of other link building tools available, but this should be a good start if you’re looking to build out your toolbox!
What’s the Difference Between Links and Referring Domains?
When undertaking link analysis or link building strategy, it’s important to understand the distinction between links and referring domains. They mean different things and should be considered in different contexts when measuring links.
Links (or ‘backlinks’ or ‘external links’) are the total number of individual links from external websites. That might be 1 link from 1 domain, or in some cases many links – if a single website links to you 10,000 different times, that counts as 10,000 individual links.
Referring domains (or ‘linking domains’ or ‘linking root domains’) are the number of separate websites linking to a site. To use the example above, even if a site links to you 10,000 different times, this would only count as 1 referring domain.
This is a worthwhile distinction to make because different measurements will draw different conclusions when analysing links. Generally speaking, we see a higher correlation between the number of referring domains and how well a site ranks, than we do when measuring this against total links.
This draws the following conclusion — the number of referring domains is a more important metric than total links, and the more referring domains a website has, the better it will probably rank. To give a simple example, all things being equal it would be better for SEO to have 1 link each from 100 different referring domains, than to have 100 links from a single referring domain.
There are, of course, many caveats to this example (such as relevancy, trust, and other quality considerations), but it can be a useful rule of thumb when measuring links.
What Are the Best Link Metrics?
We’ve found the best overall link metric to be the number of referring domains. However, many in the SEO industry seek to measure quality as well as quantity.
Many well-known link analysis tools have their own proprietary metrics to estimate link quality (e.g. Domain Authority, Domain Rating, Trust Flow etc.), most of which are perfectly useful as an indicator of link quality, but it’s worth taking these metrics with a pinch of salt.
Search engines do not use these metrics within their scoring, so keep that in mind when undertaking your own link analysis. For example, a link from a website with low Domain Authority shouldn’t be written off as a poor quality link if the linking site is highly relevant and likely to drive good referral traffic.
How Many Links Do I Need?
The amount of links your website needs is dependent on many factors and ultimately on what you want to achieve. Furthermore, the amount of links you need is a moving target – you have to assume that your competitors are consistently investing in marketing and link building to grow the size of their link profiles, so similar investment and growth over time is likely to be required.
A good place to start is to measure the amount of links and referring domains your key competitors have, and use this as a benchmark to work towards. Tools like Moz, Ahrefs and Majestic all have domain comparison tools where you can compare link metrics at a domain or page level.
Moz also have a SERP analysis tool, which helps to show how many links the top pages and domains have for a particular keyword. So if you want to get an indication of how competitive a particular keyword is, and how many links that might be required to rank for it, the Moz tool should help.
How Do I Scale Link Building?
Scaling link building is one of the most challenging aspects of SEO. Links are a precious commodity which every website needs, so finding ways to generate links at scale is hard.
As outlined throughout this guide, link building success is often intrinsically linked (no pun intended!) with so many other aspects of marketing, brand, website performance, user experience, and psychology. Link building is important to focus on, but should be done so in the context of the big picture too.
Investing in activities which deserve attention (and links!) is critical to scaling link building. Whether you are producing content marketing campaigns, digital PR work, or any of the strategies outlined in this guide, your activities should be able to earn links naturally.
The most effective scalable link building adds value to users. It influences and inspires, rather than sells. It tells a story and connects on an emotional level, compelling others across the web to share.
So whatever your approach, think about the core purpose and values of your brand or business, what you want to say and why you want to say it. That will give you the best chance to attract links at scale, and to make a real difference to your SEO performance.