SEO basics: link building—the right external links

From a technical per­spec­tive, a link (short for hyperlink) is a source reference within a hypertext, and is one of the most prominent features of the internet. With links, users are not only able to get from one website to another, they’re also able to navigate more easily through the various subpages of a par­tic­u­lar site. To reflect this, it’s important to make a clear dis­tinc­tion between external links (ref­er­ences from one website to another) and internal links (ref­er­ences on pages within a single website). Linking plays a crucial role in search engine op­ti­miza­tion (SEO) and can be put to great effect by website operators. The term used to describe SEO measures for improving external linking struc­tures is link building. In recent years, however, the methods that website operators once strongly relied upon have ex­pe­ri­enced some sig­nif­i­cant changes. This article lays out some of the basics of link building and how external links can help you achieve success with your own website.

As an SEO sub-dis­ci­pline, the purpose of link building is to first and foremost improve a site’s ranking in search engine result pages (SERPs). Links referring to a site’s in­di­vid­ual pages is one criterion that searches rely upon for de­ter­min­ing a site’s im­por­tance. In order to achieve the best ranking possible on the SERPs of Google, Bing, Yahoo!, et al., it’s important to make sure that your website is linked to as much as possible: when high-quality web presences reference your site, its vis­i­bil­i­ty in SERPs will increase.  In order to achieve this, so-called backlinks are placed on other websites. Backlinks act as back ref­er­ences for your own website and can be un­der­stood as a rec­om­men­da­tion or en­dorse­ment of quality.

Such rec­om­men­da­tions may come in the form of a guest post, for example, whereby the author publishes content on a separate website and refers back to their own site with a link. These marketing measures all belong to the sub­cat­e­go­ry off page op­ti­miza­tion, given that backlinks are placed ex­ter­nal­ly. Con­sid­ered from the per­spec­tive of the site operator who’s placing the link, backlinks are also referred to as inbound links.

Links normally increase the vis­i­bil­i­ty of a linked site on search engines. The criteria that search engines use to determine a site’s ranking have gone through sig­nif­i­cant changes, however. It used to be the case that the number of inbound links de­ter­mined the im­por­tance of a website. This feature was measured with the PageRank value.

In the past, this value was the most important basis for de­ter­min­ing a site’s ranking: the higher a website’s PageRank, the more important the search engine perceived the site to be, and the better ranking it finally achieved in SERPs. Simply put, Google used the PageRank value as an indicator for de­ter­min­ing whether a site is relevant for readers. The algorithm re­spon­si­ble for this value de­ter­mined the PageRank’s level as follows:

• The more links a website receives, the more relevant it’s con­sid­ered.
• The more relevant the linking site is, the more the linked sites profits from such citations.

There are many problems regarding this value’s strict quan­ti­ta­tive mea­sure­ments: for one thing, neither quality nor content (or the interest of the content for readers, for that matter), are deciding factors for a site’s PageRank score. Instead, only the number of inbound links counts. What’s more, the PageRank value can be ma­nip­u­lat­ed in many different ways, a fact that hasn’t gone unnoticed by those looking to profit from its short­com­ings. Search engine spamming and link spamming are two ques­tion­able practices that have arisen within this context. Through dubious means, known al­go­rithms used by search engines are exploited in order to gain a better page ranking.

PageRanks ma­nip­u­la­tions work against organic link growth, because when it comes to naturally de­vel­op­ing an internet presence, the quality of the site de­ter­mines both pop­u­lar­i­ty and how often that site linked. Es­sen­tial­ly, if an online presence is genuinely relevant for users, its pop­u­lar­i­ty ought to con­tin­u­ous­ly increase, leading to an increase in backlinks. Not long ago, many website operators took advantage of different methods to simulate the natural growth of links, which would then increase its re­spec­tive PageRank rating.

• Buying and renting links: This term generally refers to the paid placement of backlinks on other websites. The page on which the links are placed are often bear little or no thematic relevance to the linked content; instead these pages merely serve as a link platform (see link farming and link networks).
  
  
• Link farming and link networks: This applies to web presences whose main goal is to simply be linked with different websites. Most of the time, relevant content cannot be found on such pages. Website operators are able to buy a certain number of links via link farming and link networks, allowing them to quickly build a large backlink profile for their own online presence.
  
  
• Excessive link exchange: A link exchange occurs when two or more websites link their online presences among one another. This can either be an entirely natural process, such the pub­lish­ing of a guest post, but it can also happen on a far larger scale to fa­cil­i­tate bulk ex­chang­ing. Such excessive link exchange (e.g. through the use of link exchange networks) aims to increase a website’s vis­i­bil­i­ty on search engines.
  
  
• Links in comment sections and forums: The comment sections of websites, blogs, or social media platforms often prove to be valuable cyber real estate for planting links. Forums and Wiki posts also lend them­selves to placing such links, a fact that website operators commonly exploit in order to build backlinks. Links that are com­mer­cial in nature and don’t add any value to dis­cus­sions within forums or Wiki articles are perceived as spam by most users. Some websites have responded to this practice by au­to­mat­i­cal­ly labeling links placed by users within the comments section with a nofollow attribute, thereby rendering them valueless for SERP rankings.

Fur­ther­more, the PageRank algorithm sig­nif­i­cant­ly increased the trade of expired domains - web addresses that were once high in value but have become disused and free for reg­is­tra­tion. When such domains have a positive backlink profile, which remain intact even after the previous owners have dereg­is­tered, their rep­u­ta­tion can be leveraged to give an unfair advantage to newly reg­is­tered sites.

The link building methods mentioned above achieved wide­spread success, allowing many sites to climb the SERP rankings, often without improving the site’s quality. In this sense, these methods are dishonest because the intention is merely to improve a site’s ranking rather than offer the user quality content.

In reaction to such SEO methods, Google in­tro­duced the Penguin Update, an al­ter­ation to their algorithm and guide­lines for search engine op­ti­miza­tion. With Google Penguin in place, web­mas­ters run the risk being penalized for con­tin­u­ing the practices mentioned above.

Since the im­ple­men­ta­tion of Penguin in 2012, Google’s search engine has started taking other criteria into account when eval­u­at­ing links. In contrast to the prior measures, both quantity and quality now play an important role in the eval­u­a­tion of links. Most other search engines followed suit, and set up similar al­go­rithms to those of Google. The Penguin Update con­sti­tutes a new set of rules for linking, such that the afore­men­tioned link building tech­niques, when ex­ces­sive­ly employed, result in a negative effect on a website’s search engine vis­i­bil­i­ty.

In the course of Google’s in­flu­en­tial ad­just­ments to its search engine algorithm, new mea­sure­ment values for de­ter­min­ing a website’s sig­nif­i­cance have come to promi­nence. Above all else, these values aim to determine a site’s qual­i­ta­tive aspects. Two of the indexing methods include:

• TrustRank: Various trust­wor­thy websites are manually selected by search engine providers. Cal­cu­lat­ing the TrustRank takes place au­to­mat­i­cal­ly by analyzing a site’s backlink profile: it’s assumed that the pages linked to by this site are equally trust­wor­thy. For this algorithm, the more links a site receives from other sites that the search engine trusts, the more trust­wor­thy that site is deemed.
  
  
• Hilltop algorithm: With the Hilltop algorithm, websites are evaluated via backlinks that they have received from so-called ‘experts’ (i.e. pages that link to many relevant documents) on certain topics or keywords. Inbound links orig­i­nat­ing from websites from various in­de­pen­dent expert pages are regarded as authority pages.

Precisely what al­go­rithms are used by a search engines isn’t known—a large portion of our knowledge on how a search engine indexes pages comes from ob­ser­va­tions and state­ments made by those directly involved, i.e. the search engine providers. What is certain, however, is that search engines react to excessive growth in backlinks by pe­nal­iz­ing a website, es­pe­cial­ly if the linked website itself, or the site that’s linking to it, already have a bad rep­u­ta­tion.

Link building’s main purpose remains to increase the vis­i­bil­i­ty of in­di­vid­ual websites on various search engines—however, other SEO measures have since been es­tab­lished for this process as well (see following paragraph: link building as a ranking factor).

The efforts sur­round­ing backlinks are referred to as link bait and are as­so­ci­at­ed with link marketing. The main goal website operators seek to achieve here is to increase the pop­u­lar­i­ty of a link or domain. The pop­u­lar­i­ty of a link and domain of a website is evaluated based on the quantity and quality of its inbound links. In terms of quantity, each and every in­di­vid­ual link (link pop­u­lar­i­ty) and website (domain pop­u­lar­i­ty) that refers to the analyzed website is evaluated. The quality of a given link, on the other hand, is de­ter­mined by certain values of the linking website (e.g. the TrustRank, the Hilltop algorithm, etc.)

For eval­u­at­ing in­di­vid­ual links, and entire websites, search engines rely on web crawler programs (also referred to as search bots, robots, or spiders) that scan websites and evaluate them based on certain criteria. The power of a link is known as link juice or link power. To a certain extent, this link power can be trans­ferred to other websites that they’re connected to. The concept is often compared to a river from which multiple dis­trib­u­taries flow: just as water orig­i­nat­ing from one stream makes its way into different channels, link juice flows from one website to all of the websites that are linked to the site and then evenly dis­trib­utes the link power. Following this concept, the more websites that are linked, the weaker the link power trans­ferred.

Given that the link juice of other sites can be used for one’s own web presence, it’s important to pri­or­i­tize adding backlinks to pages earmarked to rise within search engine rankings. Ideally, inbound links should originate from websites that search engines consider to be of high quality. What’s more, this linking strategy isn’t just ben­e­fi­cial for search engine rankings; it also carries the potential of being able to im­me­di­ate­ly increase a website’s visitor numbers. Backlinks guide many users to websites for the first time, and if they’re then in­ter­est­ed in the content they encounter, they may end up becoming regular visitors. The chances of gaining new users increase as soon as the linked websites attain a certain level of authority and trust, es­pe­cial­ly when their thematic topics are relevant to that of their backlinks.

Generally, search engines rely on two factors when eval­u­at­ing a website’s rep­u­ta­tion. On the one hand, its rep­u­ta­tion is strength­ened the more often a page is linked; on the other, the source of each inbound link plays an important role. When a backlink is located on a website that is pos­i­tive­ly evaluated by the search engines, one that is relevant and trust­wor­thy, this increases the site’s pop­u­lar­i­ty more than when the link has been placed on an unknown or neg­a­tive­ly perceived website.

Generally, the following should be noted: the more well known the website providing the link and the higher relevance its content has to the backlink’s topic, the better the con­di­tions are for an improved website rep­u­ta­tion.

Since Google’s Penguin Update, natural link growth, or at least link growth that appears to be natural is what counts. What’s certain is that the search engine wants to see growth in a website’s pop­u­lar­i­ty occurring through valuable content. The quality of the web content should always be the top priority when inbound links and link building in general are concerned. This fact, however, doesn’t make it par­tic­u­lar­ly easy for newer websites to build up a good rep­u­ta­tion with search engines, even if the content quality is more than adequate. Given that brand new domains don’t have any entries within the search engine yet, a good rep­u­ta­tion needs to first be built up step by step in order to win over the trust of the search engine. This process can be sped up with the help of the following methods:

• Creating content that is conducive to backlinks: Simply put, good content is more likely to be linked to than bad content. This is why a website’s quality is such an important means for naturally gen­er­at­ing backlinks. In addition, certain types of content tend to be linked to more often than others: images and in­fo­graph­ics, tips and tutorials, so-called ‘listicles’, expert columns and in­ter­views, and humorous content are all par­tic­u­lar­ly popular.
  
  
• The right link en­vi­ron­ment: It’s often not up to the website operator to decide which external sites link to their own website. However, one should always be aware of which sites are linking to yours, and in the event that a web presence with a less-than-reputable image has cited your page, then demanding its removal may be in order. Failure to take any action could result in the backlink doing more damage than good. When the language and country between the linking and linked sites differ from one another, then this too can be damaging to the page. For those looking to get in touch with a website in order to exchange links, it’s important to find out be­fore­hand whether the potential partner website is an ap­pro­pri­ate en­vi­ron­ment for incoming links. Moreover, websites with high rankings provide more link juice to your own page.
  
  
• Natural link exchange: There are many scenarios where mutually linking two websites is ben­e­fi­cial to both parties, such as when a theme-ap­pro­pri­ate guest entry is placed on a similar website. Blogs also provide blogrolls—a list of other relevant rec­om­mend­ed blogs—which can be used to exchange links.
  
  
• Using deep links: Those who are able to influence the inbound links to their own web presence, through an organic link exchange or other measures, should also consider using deep links. Deep links are ref­er­ences to a subpage of an website as opposed to surface links, which are only linked to a site’s home page. Deep links are valuable because they help certain pages or landing pages increase their domain pop­u­lar­i­ty.

In essence, the more links that search engines like Google and Bing recognize, the better the placement of the linked site in the SERPs. Remember, the amount of links isn’t every­thing: the en­vi­ron­ment and the rep­u­ta­tion of the source websites are just as important. A smartly con­struct­ed link profile can have a positive effect on both the ranking of in­di­vid­ual web pages as well as the number of hits to the website as a whole.

Even in the era of Google Penguin, it remains possible for internet presences to profit from external links. Moreover, there are tools available for many link building measures; these can help aid in your efforts to implement different link bait campaigns. When link building, it’s important to always be aware of the fact that quality is the highest priority, and both the desires of your target group and the guide­lines set by the search engines should be taken into account. Those who respect these rules sow the seeds for a fertile en­vi­ron­ment in which natural link growth can flourish.