Link building – connections as a reference for search engines

30 min

What is linkbuilding and why do you need it?
Back to basics – What is a link anyway?
Backlink types
Most important characteristics of a link profile
From anchor text to placements to quantity – do’s and don’ts of link building
The most important Google updates in link building
Link building strategies – concrete measures and techniques of link building

Linkbuilding tools that make your life easier
Free tools
Paid tools

What is linkbuilding and why do you need it?

The image shows a schematic link building structure. From the main page, links are made to many other pages. This can be done by internal, but also by external linking.

Linkbuilding is a measure of search engine optimization (SEO), more precisely from the area of OffPage optimization. In SEO, a distinction is made between OnPage and OffPage optimization, whereby the first deals with structural and technical improvements to the content of the website. OffPage optimization includes all measures outside the own page. Above all, it is still today about the collection of backlinks. These are links that refer from the website of a third party to one’s own. Google evaluates such links as recommendations for the linked target page. In the long run, this can have an effect on the ranking in Google search results and makes your site more findable on the web. In the past, however, attempts were often made to deceive Google. This happened, for example, through the spam-like placement of links by webmasters. As a result, the guidelines became stricter, which is why the influence of a link does not necessarily have to be positive. Nevertheless, even today, there are various link building strategies and link types that improve the ranking. However, on the other hand, there are the methods that are negatively evaluated or even punished by Google in the worst case. In modern and Google-compliant link marketing, it is therefore important that you pay attention to the quality and a reputable origin of the backlinks.

Back to basics – What is a link anyway?

Everyone knows it, everyone has clicked on it dozens of times. Trademark: Blue and underlined – the link.

Hyperlinks – or links for short – are cross-references between two web pages. They allow you to jump from one web page to another. The elementary components of a link are:

The anatomy of a link in HTML code looks like this:

The image shows a schematic link building structure. From the main page, links are made to many other pages. This can be done by internal, but also by external linking.
The anatomy of a link in HTML

However, links are not only used to connect two web pages, but can also refer to videos, images, animations or files. Moreover, they can even trigger a download or start other actions. The main purpose of a link is to increase usability, as the user is very easily granted access to relevant additional information or further content.

Backlink types

A basic distinction is made between:

While internal links are important in the course of OnPage optimization, only external links are relevant for link building. Links created here are also called backlinks or inbound links. In the HTML code, to define the relationship of the linking more precisely, a rel attribute is inserted after the reference in the anchor or <a>-tag. It then looks like this:

The image shows the schematic HTML structure of a link with rel attribute.
HTML structure of a link with rel attribute

The rel-attribute can have the following values:

AlternateAlternate document (same content, different document version)
BookmarkReference point
ContentsTable of contents
CopyrightCopyright notice
HelpHelp context
NextNext file/page
NoOpenerComes in conjunction with target=”_blank”
→ prohibits new tab from accessing contents of previous page
PrevPrev Previous file/page
SearchSearch function
SponsoredContent/links generated by financial consideration
UGCUser generated content

However, the most commonly used value is NoFollow. This attribute sends Google the sign that the link should not be “followed” or the link should be disregarded. The direct counterpart, the DoFollow or Follow tag for short, is therefore not necessarily to be specified, as the bot always crawls links if it does not receive any other instruction.

In addition to Follow and NoFollow, there are other significant link types:

Spam linksSocial linksVideo & image links
Links to pages with keyword stuffing resp. “MoneyMaker” pages, lots of links from dubious sources, unnatural link profiles, etc.Are placed in social media.In Videos eingearbeitete oder hinter Bildern hinterlegte Links.

Different link types are important for a natural link profile (except spam links, of course). However, follow links are mainly influential for Google ranking.

But be careful: The source of origin has a decisive influence on the value and quality of the backlink. Not every follow link automatically improves the ranking. Therefore, first check the page on which the link is to be placed.

Ask yourself the following questions:

  1. Does the website make a serious impression?
  2. Does the website fit thematically to my own page?
  3. Can a link be placed there reasonably?
  4. Has the website already been penalized by Google?
  5. What is the visibility index of this site? Does it remain constant, fall or rise?
  6. Are there many spam links, or is it possibly even a pure link seller site?
  7. Is there a normal imprint or only a picture imprint, or possibly no concrete information at all?
  8. Is the page and especially its content up to date or already outdated?

Remember: “Quality over quantity” counts!

In addition, you should look at both the domain and the link popularity. The domain popularity shows you how many pages link to the website on which you want to place your link. The following applies: The more domains already link to it, the higher their domain popularity. This in turn gives you information about how respected the page is on the net. Another important keyword in this context is the domain authority. In principle, this says the same as the domain popularity, but is often called differently. About the link popularity you can draw conclusions about the quality of the backlinks.

Most important characteristics of a link profile

When talking about a link profile, the word “natural” is inevitably mentioned. But what does “natural link profile” mean?

A link profile is the term used to describe all the backlinks that a website has. These can be analyzed on the basis of various key figures and thus get an overview of the quality of the whole linking.

To be able to judge the link profile well, a backlink analysis is necessary. You should pay attention to the following key figures:

A natural link profile always has both follow and NoFollow links, as this reflects a clean link structure. Thereby, links are created from small, but also from large websites. In addition to the ratio of Follow and NoFollow links, it must also consist of a variety of different link types.

Especially links from the following areas are often marked with rel=”nofollow” and therefore have little influence on the Google ranking of your own page:

Competitor comparisons help you to determine the ideal proportion of follow and no-follow distribution. If you find a deficit on your page during this analysis, you should build appropriate backlinks. You can use different tools for this, which you can find in the section “Linkbuilding tools that make your life easier”. Through appropriate measures, a natural link profile is created in this way. This is perceived by the Google algorithm as a positive signal, which in turn improves the search engine ranking.

A natural link profile is just a colorful mixture.

A regular backlink audit is important to maintain a natural link profile. Only by continuous monitoring you can avoid that links, which were not explicitly initiated by you, harm the ranking of your website. Content often spreads automatically on the internet, which in turn leads to organic links. In addition, competitors can deliberately build negative links pointing to your site. If you notice something like this, it is advisable to contact the webmaster personally and ask him to remove the link. If this does not work, there is a special tool from Google: The Disavow-File. With this you can devalue links in the Google Search Console. After that, the link will no longer be evaluated and can no longer harm your ranking.
However, working with the disavow file is a bit complicated. Therefore, it is best to go to a professional who can help you.

So this is how natural and unnatural link profiles differ in detail:

CriterionNatural link profileUnnatural link profile
Link types – Article marketing
– Original content
– Forum posts
– Blog comments
– Social Signals
– Links and catalogs of inferior quality
– Blog roll links
Quality of linking websites – High domain authority
– Trustworthiness
– High quality content (also with the
– Up-to-date & unique content
– Content that is only designed for SEO & not user-oriented
– Outdated web pages
Anchor textsMix of:
– Longtail keywords
– Synonyms
– Phrases with keywords
– Brand names
– Pure keyword
– Keyword stuffing
– Too frequent use of money keywords
– Too frequent use of attention-grabbing keywords
Relevant content – Relevance to the topic – Links from areas that are not directly related to the topic
Link growth – Continuous
– Especially growing when new content or
content or announcements appear
– Strikingly large jumps within a short period of time
– Growth inconsistent with content publications
Source mix – Many different sources – Few/limited number of sources
Link origin – Serious origin of links matching the domain – Links with questionable origin

From anchor text to placements to quantity – Dos and Don’ts of link building

There are some principles that definitely need to be followed in link building. Likewise, there are some points to avoid.


  1. Build a blog into your website whose content can be shared and commented on.
  2. Produce high quality, unique, current and relevant content for the user.
  3. Use only authority websites with reputable mastheads.
  4. Try to make the anchor text as varied as possible and only as keyword-heavy as necessary. Also, use relevant link titles that fit the context of the target page.
  5. Be sure to use the same URL for the Googlebot and your users. Never display different content for both.
  6. Try to get as many follow links as possible for your website.
  7. Enable sharing of your content via social media platforms.
  8. Create interesting value-added content, such as infographics, checklists, videos, how-to’s, studies, etc. that add value to your users.
  9. When linking, make sure the link target is relevant to the topic.
  10. Regularly check your link profile and remove bad links.


  1. Never work with low-quality blogs, spam sites or dubious websites.
  2. Do not buy into link networks.
  3. Don’t use automated programs that distribute links on the internet.
  4. Avoid too many footer or sidebar links.
  5. Don’t rely too often on hard keyword phrases in your anchor texts.
  6. Forum links have no influence on Google and do not help you to improve your ranking.
  7. Do not submit to low-quality directories.
  8. Do not use hidden links, for example, white text on a white background.

The most important Google updates in link building

The most important Google updates in link building at a glance:
In 2011, everything started with the Panda update, which was followed by the Penguin update in 2012. In 2015, Google followed up with the Mobile-First Index and in 2017, the Fred update enriched link building.
The most important Google updates in link building

Google continuously updates its algorithm with updates and data refreshes. However, they do not always hit every area of search engine optimization. Below you can see the most important updates that have had an impact on link building.

2011: Panda update

This update is a filter that influences the entire Google index. Its goal is to detect poor quality websites and devalue their visibility. The focus is therefore on high-quality and unique content that offers the user added value. What is exciting here is that the update affects the entire website or entire category areas of it, while preliminary updates always hit only individual pages.

After Panda, good, user-oriented websites will therefore be displayed higher up in the SERPs. The quality of these pages is determined by the following, among other things:

2012: Penguin update

In addition to the Panda update, Google has refined its algorithm with the Penguin update. Again, this is a quality filter that penalizes misbehavior and therefore changes the rankings of websites.

While the Panda update checks website content, the Penguin update takes care of spotting “web spam”. This means that all techniques of the webmaster that only serve a ranking improvement, but not the user, will be punished. This includes for example keyword stuffing or cloaking – you can find more techniques of this kind below.

This update is the most important one for link building, as it aims at penalizing especially nonserious and unnatural link building.

2015: Mobile First Index or Google Mobile Update

Today it is impossible to imagine a website without the smartphone, but this was not always the case. In 2015, Google decided to jump on the growing trend of mobile search and make it easier for users to search via smartphone. The main consequence of this update was that websites gradually had to make a mobile adaptation in the form of a responsive design or a mobile website in order to rank well. Therefore, for link building, it was also important that the distance between individual links was large enough so that they could be clicked easily. They also need to be formatted and placed in a way that is easily visible to the user.

2017: Fred update

There was also a change to Google’s core algorithm with the Fred update. Once again, this optimized the ranking criteria to further increase the quality of page content. As usual for Google, the focus is on added value for the user. Several factors therefore influenced the ranking:

Therefore, similar to Panda and Penguin, the Fred update attacks pages that are not designed to benefit and add value to users, but only to improve rankings within search results.

Link building strategies – concrete measures and techniques of link building

In principle, the various strategies can be divided into three main categories: Black Hat, Grey Hat and White Hat link building.

The picture shows schematically Black Hat-, Grey Hat- and White Hat-Linkbuilding. This is represented by a black hat on a light gray background, a gray hat on a medium gray background, and a white hat on a dark gray background.
Black Hat-, Grey Hat- and White Hat Link building

A distinction is made between how strictly Google’s quality guidelines and generally applicable laws are observed and adhered to. While White Hats consistently adhere to all guidelines, Grey Hats may violate one or the other. The last group, the Black Hats, on the other hand, act freely according to their own arbitrariness and don’t give a damn about all the quality guidelines Google prescribes.

Black Hat link building methods

These strategies are not designed to increase the user experience. They are only intended to boost the website and improve the organic ranking within the search results. Meanwhile, Google’s algorithm recognizes such violations of the quality factors relatively well and punishes or devalues the website accordingly.

Nevertheless, there are various methods that are used among the “black sheep” of SEO:

  1. Spam-like commenting on third-party websites.
    Often, the link of the page is spread via the comment fields of various websites. The content of the posted page is most times not relevant to the topic and therefore not important for users. The sole purpose is to spread the link. Some users do something similar with their usernames. Here, the link is simply written behind the name. So it is not in the comment field, but still counts as comment spam.
  2. Link Farms
    Link farms are websites that primarily have the purpose of collecting outbound links. There is no connection or relevance for the user.
  3. Automated setting of backlinks
    There are various software programs like XRumer or Scrapebox that create links fully automatically. These links are then placed spam-like on various websites.
  4. Private Blog Networks (PBN)
    Here, a network of several domains, usually blogs, is set up, all belonging to the same person. These are then used to build backlinks relevant to the topic.
The picture shows the schematic structure of a private blog network. Here, the target website is at the center of it all and various private blogs link to it.
Structure of a Private Blog Network
  1. Cloaking
    With cloaking, users get a different view of the website than the search engine crawler. In this way, content is adapted to the user group. While search engines are delivered pages that are text-heavy, humans receive a more visually appealing version.
  2. Expired domains
    Expired domains are domains that have been deleted by the respective registry or will be deleted in the near future. It is possible to buy them and then take over the backlinks of this site.
  3. Invisible texts
    White text on a white background – making written text invisible to the user, but visible to the search engine – has been a popular black hat method for a long time.
  4. Negative search engine optimization
    Negative SEO deals exclusively with causing damage to the competition. This is usually done by targeted placement of links of the competitor in the bad neighborhood or by spamming with the same anchor text over and over again.

All these measures have only one goal: to greatly improve the ranking of one’s own website within the shortest possible time. However, since they violate Google’s guidelines, websites that practice these methods are penalized and thus tend to worsen rather than improve.

Grey Hat link building methods

Grey Hat link strategies are, as the name suggests, in a grey area. They are not necessarily illegal, but they are not always good for your website. You should therefore carefully consider whether you want to take the risk and use these methods.

  1. Link buying
    As the name suggests, this is a method in which backlinks are purchased. Search engines value quality. This is only the case if a topic-relevant article links to your own website. With links that are bought in link buying networks, this is often not the case. Therefore, this is not a sign of quality and is thus penalized. However, if you place a link with a thematically appropriate webmaster, it is okay to pay him for his time and effort.
    Links should be natural and based on relevant and good content.
  2. Link rent
    Similar to link buying, link renting involves paying a fee to be able to place a link with a webmaster. The difference to link purchase is that the link is limited in time and goes offline again after this period or is deleted by the webmaster.
  3. Link exchange
    The term is actually self-explanatory. One website links to another, while the latter links back to the former. This also does not necessarily reflect the quality of the content, but rather a successful agreement.
Here you can see a schematic link exchange between two websites. This is represented by a fictitious website A and a fictitious website B, in the middle of which there is a link icon framed by two rotating arrows.
Link exchange between two websitesten
  1. Entries in blogs, directories, guestbooks, etc.
    The entry of one’s own website in directories, guest books or on blogs is per se only useful if there is subject relevance to the corresponding page. Otherwise, links placed here are rather harmful.
  2. Keyword stuffing or always using the same keywords in the anchor text
    The mass use of keywords in the anchor text or the setting of always the same link text is also penalized by Google. Natural link phrases that are adapted to the context are better here.

White Hat link building methods

If you want to be on the safe side and avoid penalties, white hat methods are definitely the way to go! You can’t go wrong with this, as Google accepts these methods and doesn’t devalue links that originated from them. Again, there are plenty of strategies that will make link building easier for you.

  1. Establish contacts
    One of the best methods is to build a network of good contacts. This can consist of cooperations, customers, partners, suppliers, non-profit organizations, etc. It is important to approach them personally, directly and honestly. In addition, it should be explained to the contact what the purpose of backlink building is and what benefits it will bring. This way, the chances of an acceptance are much better.
  2. Write guest posts
    If you offer the webmaster a guest post, you must make sure that it is absolutely free of advertising. Otherwise, the link must be marked as a sponsored link. Nevertheless, it is a good way to create high-quality content that links to your own website. Make sure that the webmaster’s site is a reputable source and that the target audience or industry fits.
  3. Analyze competitor backlinks
    A competitor analysis never hurts to know your own status quo and close any gaps. But at the same time, you can check the different backlinks of the competition via different tools. This way you can find out more potential link providers. If the direct competitor is linked on a page, your own interest is of course great to be mentioned there as well. The only important thing is to make sure that the page you want to link to is relevant to the topic and offers added value for your target group.
  4. Restoring dead links (broken link building)
    Dead links? Yes, they exist. They occur when a link leads nowhere or has never been linked to a resource. These “Broken / Dead Link” are usually recognized by the display of 404 Not Found pages after the link has been clicked. With different tools, you can find such broken links and ask the webmasters to use your page as link target.
  5. Google Alerts
    Google Alerts is a notification tool of the search engine. It emails you as soon as your predefined search term is mentioned on a web page. This can be mentions of the company name, a product, or posts about certain keywords. It all depends on what keywords have been pre-determined and whether you are aiming more to find potentially matching pages on certain topics or to reach out to webmasters who have mentioned you.
  6. Turn mentions into backlinks
    Asking the webmaster who has already mentioned you for a link – you can’t really have it any more uncomplicated than that. But how do you find these mentions? One possibility is Google Alerts. Additionally, you can search the SERPs, the search results. There are also various tools that make it easier to find mentions.
  7. Reverse image search
    Sometimes images are used by third parties without linking to the author. You can take advantage of this circumstance with the help of Google’s reverse image search. To do this, you can either insert an image URL via the camera icon (see picture below) or upload the image directly. Google then locates the pages that use the image. You can then ask the webmaster of this page to include the copyright notice with a link.
You can see a screenshot of Google's image search. Users can use this not only for pure image searches, but also as a reverse image search by entering the image URL there or uploading the corresponding image. All pages that also use these images are then displayed.
The reverse image search on Google
  1. Link bait
    Link bait or clickbait tries to get a lot of traffic for a project in the most natural way possible. In this method, webmasters are “lured” by strategies such as sweepstakes, top 10 rankings, test results, blog rolls, etc. This makes it possible to get other users to talk about the website with relatively little effort. Through this, it is possible to get other users to talk about the website and link to it with relatively little effort.
  2. Internal linking
    Not only external links are important, but also internal links are an important factor for search engines. These weight the content of a domain and create an order or ranking. Since all internal links lead back to the home page, this is the most heavily weighted. Links that originate from the home page also contain the most significant content. So this method should not be underestimated.
  3. Good content
    The most obvious one ends up being the method that is most often not considered: Creating good content that is worthy of being shared. Classic content marketing, in other words. Once you’ve done that, links build all by themselves. The content must be innovative and unique. You can achieve this through infographics, interactive content, engaging and informative texts, helpful guides, surveys, explainer videos and the like.

Link building tools that make your life easier

There are various tools that will make link building easier for you. It is best to use different tools, because one tool alone often cannot check all links one hundred percent. On the market you will find a variety of free and paid tools. Here you get a rough overview of some of the most practical tools.

Free Tools

    This tool helps you to create a Disavow file for the Google Search Console. There is also a function “Apply Disavow File”. This function compares a list of URLs that should not be recognized as backlinks with an already existing disavow file. In the next step, this is cleaned up. Afterwards, it can be uploaded directly in the Disavow Tool of the Search Console.
  2. Moz Link Explorer
    This tool is suitable for analyzing a complete URL. It checks not only the backlink profile, but also the domain authority. However, you need a Moz account to use the tool for free. Since you can check a maximum of ten domains with the free version, you will need the paid version as soon as you exceed this number.
  3. is a useful tool for finding e-mail addresses of individual contact persons of companies. To do this, you require entering the company URL on the site, whereupon you will receive the addresses of the employees. Up to 50 requests per month are free of charge.
  4. CheckMyLinks
    CheckMyLinks is a free Google Chrome extension. It is one of the easiest link building tools and helps you to generate high-quality backlinks. It also detects dead or broken links on a website of your choice.

Paid Tools

  1. Ahrefs
    Ahrefs is the world’s largest backlink index. This tool provides an incredible amount of information. It is therefore not only suitable for traffic building, but also excellent for competitive analysis.
  2. JustReachOut
    If you are looking for journalists, podcasts, publications or broken links, this is the tool for you.
  3. NinjaOutreach
    Similar to JustReachOut, NinjaOutreach is a tool that puts you in touch with potential webmasters. However, here no journalists are suggested, but influencers and bloggers.
  4. GroupHigh
    GroupHigh, similar to the two previous tools, is designed to establish contact with bloggers and influencers. For this purpose, the various websites are filtered by date of the last post and domain authority. This process ensures that you only get active blogs with good reputation suggested.
  5. BuzzStream
    BuzzStream also allows you to find influencers who are a perfect fit for your industry. It allows you to contact them without tedious emailing back and forth, plus work as a team.
  6. Contentbird
    Contentbird, formerly Linkbird, is an all-in-one SEO tool. However, many features are designed towards linking and content creation. You can use it to monitor your links, create backlink lists that you can in turn use for other projects, and perform keyword research. All of this can also be easily edited in a team.
  7. Pitchbox
    Pitchbox is a tool that identifies the potential of possible links and builds contact with influencers. It thus sets its focus on outreach. Here, too – as with Contentbird – there is the option to work on projects in a team.
  8. Broken Link Builder
    This tool helps you track down broken, dead and non-functioning links that thematically match your content across the web. Then you can contact webmasters to offer your site as a link target.
  9. Monitor Backlinks
    Monitor Backlinks is especially for SEO newbies. This tool accesses a backlink index based on data from MOZ and Majestic. For this reason, Monitor Backlinks can give you information about new, available backlinks very quickly. In addition to that, it offers functions to monitor keyword rankings, fight negative SEO and rebuild valuable links that have been lost. Also, you can keep an eye on your competitors with this tool.
  10. Guest Post Tracker
    To increase your organic traffic and build links, you can also work with guest posts. Guest Post Tracker finds high quality blogs from companies that are exactly in line with your business sector. Bonus: Professional writers will then write the guest post for you.
    With the help of SISTRIX you can easily compare the reach of different websites. The visibility index developed by the tool makes it easy for you to compare different domains. It also allows you to weigh up whether placing a backlink on this page is worthwhile at all. In addition, the tool has a function that analyzes your link profile. So you have the possibility to analyze the ratio of deep links to the start page on the one hand and the ratio of follow to no-follow links on the other hand.
  12. Majestic
    Majestic is an SEO tool that checks the links of websites. For this purpose, the entire link profile is examined.
  13. Searchmetrics
    This search and content marketing platform offers concrete analyses of one’s own website and those of competitors. From this, the tool derives recommendations and forecasts, which in turn can be incorporated into one’s own strategy.
  14. Xovi
    This is an all-in-one tool. It therefore combines various functions:
The image provides insights into the various functions of the link building tool Xovi. These include:
- Disavow
- Link Manager
- Search Analytics
- keywords
- monitoring
- OnPage
- links
- Social Analytics

© Xovi
Xovi functions, © Xovi


All in all, you can see that link building is a very complex measure of off-page optimization and definitely has its right to exist in search engine optimization. Various tools and strategies help you to spread your website on the internet in different ways. So you have the chance to influence and improve your organic ranking in the search engine results.


What is link building?

Link building describes methods that have the goal of expanding one’s own backlink profile and obtaining high-quality references from external sources to one’s own website. As part of SEO, it falls under the area of OffPage optimizations, since all measures take place outside of one’s own website.

What are backlinks?

Backlinks are links or references from a third-party website to your own.

Why are backlinks and link building important for search engine optimization?

Google evaluates backlinks as recommendations for the linked page. This shows that other webmasters find content interesting and worth linking to. This sends Google the signal that corresponding content can be relevant for users and offer added value. This in turn can have a long-term and sustainable effect on the ranking in the search results.

Can you rank on Google without link building and backlinks?

Sure, you can rank well without link building and the resulting backlinks. Nevertheless, with good content, it will always be the case that external websites link to this content – simply because it brings added value to your own readers. A page completely without backlinks is therefore rare. However, if you want to rank for keywords that are highly competitive, you should definitely rely on link building to set yourself apart from your competitors.

What is black hat link building?

The attempt to deceive Google and build backlinks through non-Google compliant measures is called black hat link building. Google recognizes these methods very well and punishes them. Reason: quantity often takes precedence over quality. The user experience and the added value for the user is often worsened instead of improved.


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