Why do we link to other websites?

New research shows that organic links on the web often exist for explicitly promotional reasons.

A study of linking behaviour on the web was conducted between May and June 2016 in hope to understand the following:

  • Why web publishers link out to other websites.
  • What regular web users think about links.

Quantitative study involved over 2000 respondents from Australia and USA showing a surprising number of users who consider promotional and commercially-driven reasons to be primary purpose of external links on the web.
links perception

Question: What do you think is the main reason for a page on one website to link to a page on another website?

Most of us in the SEO industry consider relevance and context a hallmark of true “natural links”. Surprisingly only one in five respondents see links that way. Analysis of open-ended answers highlighted several prominent categories created by clustering of related answers. “Marketing, Advertising & Revenue” surfaced as the most prominent theme with one in three web users considering links to be of mainly promotional nature. Even if we merged “Access and Convenience” (11%) with “Relevance, Context & Detail” (20%) it still wouldn’t beat the top reason, especially if we added “Promotion, Relationship & Sponsorship” (9%) and “SEO & Traffic” (5%) to it.

Commercial vs Noncommercial

Further analysis involved merging of commercial and noncommercial reasons behind external links showing that most web users consider links to be of explicitly promotional nature (including personal gain or purposely promotion of third parties):
links sentiment

Updated Link Classification

Back in 2013 we performed a similar study and found eight primary reasons why links exist on the web. Since then I’ve also added “Proof” as a category and as of today I’m introducing “Promotion”.

  1. Attribution
  2. Citation
  3. Definition
  4. Expansion
  5. Identification
  6. Example
  7. Action
  8. Relationship
  9. Proof
  10. Promotion

The above reasons are overlapping in nature and can be combined in any number of ways. For example linking to a page to show “Proof” and back your statements can also imply “Expansion” where users are not only checking on the validity of your statements but also expanding the subject matter and going deeper into research.

What does this mean?

This creates an interesting problem when evaluating links on the web, regardless of whether you are part of Google’s search quality team or work SEO-side. We’re often lead to believe that “commercial anchor text” is a bad thing and an open invitation for penalties. When performing link clean-ups, webmasters are advised to remove, nofollow or disavow commercial links from their link profile. Guest posts, sponsorship and business partnerships all fall under this category. Yes there’s abuse in all of these categories but there are also many legitimate cases. So who has the right to decide if a link is “inorganic” because it’s of promotional nature when we know that organic links do exist to promote things.
Consider the following post, and its “natural looking” anchor text “in May, 2015”. A link of this type will never trigger a penalty, it’s utilitarian and obviously useful to readers:

  • It supplies context and background information.
  • Expands topic by providing additional detail.
  • Gives users optional access to further information.
  • Enables leaner, more digestible content.

But here’s the catch. AlchemyAPI (linking) and IBM Watson (linked) are in a business relationship and the link is of a promotional nature. In addition to this, the two authors (linking and linked) could also be friends and wanted to promote each other’s product or story to gain popularity, traffic and sales. And this is normal.
I see a lot of websites nofollow links to their partner websites, sister companies and various other forms of affiliation because they were told to do so by their SEO or even someone in Google’s webspam team. This sort of madness has to stop. If commercially-driven links exist on the web organically then they’re organic in nature and shouldn’t be treated as “clean-up material” nor should those links be penalty-yielding.

Highlights From Quantitative Study

Our webmaster interviews revealed fewer commercially-driven reasons and focused more on value and user experience:

  • “To provide value to my readers is the most important reason. Depending on the site it may also help bring attention to your own blog if they are tracking their traffic.”, Reeva
  • “Mainly to provide additional information/resources for visitors/readers. Occasionally to point visitors/readers to other in-house web-properties.”, Sasch
  • “Because i think there are further, useful, more holistic informations for my users.”, Helmut
  • Credit for source material, provides my content context, provides an excellent resource for my readers.”, Paul
  • “When referencing an article, citing a contributor or author”, Tim
  • “If the website has the full research that I have referenced within my article. if I have used an image/infographic to include in my post.”, Rebecca
  • “I see it of value to others, it resonates with me personally and it may help others, or just to make people aware of what is there (eg. I see a cool website that showcases mumpreneurs selling homemade things so I will share with mums i know who may be interested). I share links to other sites because that’s how we all learn and grow and that link you shared could have a big impact on somebody.”, Jaaved
  • “Provide additional information to support my claims.”, Lee
  • “To refer the reader to a more detailed page about a topic/term that is mentioned in my article. To acknowledge copyrights of content used in my articles, 3 to refer the reader to a shopping page where he can found an offer or a product I’m reviewing in my article.”, Giuseppe
  • “To provide additional high value complementary information.”, Panela Philpot
  • “We link to other websites to let the website know that we find their published content valuable and credible. It works on both ways. I personally believe in the value equity. Of course, we want our content to be of high quality and value to our readers. Linking to other sites is one way to do that. For the sites we are linking to, it’s a backlink – an important ranking signal and factor. It’s a win-win therefore.”, Jennevie
  • “To promote something (affiliate link), assist a reader, prove or explain something or borrow credibility, gain the use of a service > widget, discuss, praise, criticise or review something, exchange links. F&%k Google.”, Jim
  • “To prove post authority, improve post SEO with linking, to prove data in post”, Metehan
  • Helpful, cool, useful, credible.”, John
  • “Because it is related in article, I would like to introduce that.”, Haruka
  • “The main reason behind me linking to other websites is to help my readers navigate to the things that I am talking about. I am an SEO and Content Manager by day so I understand linking best practices and policies on linking. It is very rare that I work with a company or brand whose sole purpose is to gain a link (I have this disclaimer on my website). I much prefer to work with brands who are seeking exposure and audience reach, I then often link to them without them even asking because I believe in their products/services and want to share them with my readers.”, Shannon
  • “When there is useful content elsewhere related to my page but I can’t replicate the content. When I read an article that I think deserves linking to, I will link to it to reward the writer and as a show of thanks (very, rarely). To YouTube clips if the videos relate to the content of my page, but won’t take customers away. (very rarely, but occasionally). To my own sites, for obvious reasons 😉 Favours on a “you scratch my back, I scratch yours understanding” not very often nowadays and with very few trusted people. To sites that sell the same/similar product/service as me but who I don’t consider direct competitors. ie. services covering locations far enough away not to be a competitor product sellers in different countries.”, TJ

2023 Update

Here’s the list of most commonly used anchor text which top 10 blogs on the web use to link out to other websites:


Dan Petrovic, the managing director of DEJAN, is Australia’s best-known name in the field of search engine optimisation. Dan is a web author, innovator and a highly regarded search industry event speaker.
ORCID iD: https://orcid.org/0000-0002-6886-3211

1 Points