What are external links?

External links are links that lead to pages on separate domains. They have SEO benefits in the form of both enhanced user experience and increased authority.

What Are External Links in the Context of SEO?

An external link (also called an outbound link) is a link on your site that points to a page on a separate domain. You can also think of external links as citations. If you want to make a claim and back it up with evidence, you need to cite your source with an external link. An example of this would be social links on the Page One Power website. When we provide this link to the Page One Power Facebook page, that is an external link, because Facebook is a separate domain. 

Any kind of linking is always a two-way street. When your site earns links, those are inbound links to your domain (from your perspective), but all the linking domains contain external links pointing to your site (from their perspectives). In other words, external links are what your backlinks look like to those hosting the links. This relationship is important because the external links you choose to host have the power to send authority signals benefitting the pages and domains you link to; however, putting external links in your content can also send signals of trust and expertise that benefit your own pages and domain.

How Do External Links Affect SEO?

External links serve several important purposes as a part of a holistic SEO strategy.

User Experience

While user experience isn’t what constitutes a ranking factor on its own, it is still extremely valuable to take both user experience and search algorithms into consideration when creating blog content. If you only consider the concrete signals the algorithm assesses, rather than value and usability from a reader standpoint, the overall SEO value of the content is not as complete. Ultimately the goal of the Google algorithm is to curate content that is most useful to readers. The specific ranking signals used by the algorithm may change, but that underlying goal of serving searchers will not. Therefore, if you create content with user experience as a priority, you are more likely to create something of lasting value that is less likely to lose equity when the algorithm changes. 

External links contribute to user experience by providing the reader with easy access to useful supporting information. For example, in an article about how to fill out a tax return, it would be very useful to the reader if links to the appropriate tax forms on the IRS website were included. Rather than having to seek out that additional information independently (potentially through additional searches), or having to scroll down to a source list at the bottom of the page, the reader can simply click on the hyperlink in context, which ideally should be attached to the most relevant and descriptive anchor text

Source Citation

Source citation is another component of external links’ SEO value. External links are a means of citing your sources in a user-friendly way that does not necessitate the addition of a source list at the bottom of the page. It is important to cite your sources because it lends to the credibility of any claims you are making, as well as the credibility of your website as a whole. 

By associating yourself with other trusted experts and authoritative websites, you can make your own site and its content appear trustworthy and credible by proximity. Of course, the links you are able to earn organically are an even more powerful signal, but the relationship is still the same: citations express trust and confidence in the content of another site. When you point search engines to that content, you create deeper associations of relevance, accuracy, and quality.

And of course, citing your sources helps you avoid potential plagiarism issues, and gives all due credit to other creators and experts. For that reason alone, almost no website should be entirely free of external links.

Authority Building

When you link to relevant and authoritative content, it can reflect well on your own website’s authority and reliability. Ideally, the content that you link to should be highly authoritative, such as pages on government and educational websites, or credible news publications. It is important to note, that while many people rely on domain authority (DA) to determine the authority of a website, it is not a perfect measurement tool, and doesn’t comprehensively quantify everything that contributes to the overall authority of a domain. 

Relevance can be even more important than authority. Relevance refers to how closely related the content of a linked page is to the topic being discussed. For maximum benefit, the linked content should ideally be highly relevant to the anchor text it is attached to. For example, if your anchor text is “groom your cat regularly,” a link to a page about proper grooming techniques for a cat would be very relevant, whereas a link to a page about popular cat toys would not. 

Relevant external links to credible, trustworthy sources in your content can make your own content appear similarly trustworthy, credible, and authoritative. Again, this relationship is even stronger with backlinks you earn from other sites, but the relationship between two linked sites is a powerful signal that flows both ways.

Link Neighborhood

Link neighborhood” is a term that is not used as often as it once was in the field of SEO, however, it is a concept that is still applicable. A “link neighborhood” is an analogy that compares the network of websites that are linked with each other — in a single page, or across a domain — to a neighborhood. The theory is that just like the aesthetic and value of one house lends to the aesthetic and value of the whole neighborhood, the aesthetic and value of each individual website can similarly reflect on every other website in the network. 

Consider how you might blend external links to cite your sources, alongside internal links to your own content. If writing an article on tax laws, you might cite the IRS and a few news sources, then link internally to your own accounting software or even other blog posts you had written. The link neighborhood for your content is very authoritative here, sandwiched between the IRS and major media publishers. That is good company for your site, and the link neighborhood can confer value to your content as a result.

Just as peeling paint or criminal activity at one house may reflect poorly on the neighborhood, spammy, poor quality content on a website can reflect poorly on other websites that it is linked to. This is why both good quality external links and good quality link building is so important.

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Characteristics of Effective External Links

Characteristics of effective external links include:

  • The linked page does not serve the same searcher intent as your page (if you just rewrote the outside source’s content, why should anyone be reading your content instead of the original? Always aim to create something new, not just recycle other people’s content).
  • The link uses descriptive, keyword-rich anchor text (by reading the anchor text, visitors should be able to make a good guess as to the content of the linked page).
  • The link is to a contextually relevant page (by reading the anchor text in context, visitors should be able to make a very accurate guess as to the content of the linked page). 

The link is to a trustworthy, authoritative page (be selective about who appears in your link neighborhood to preserve your own credibility as a resource).

How Many Outbound Links Are Too Many?

So, we have established that external links can be helpful to an SEO campaign. But can it be overdone? In short, yes. However, there are no precise rules or hard numbers that determine when “enough” risks becoming “too much,” and there are always exceptions to the general guidelines that do exist. That being said, some rough guidelines for how many external links you should use are:

  • Avoid using a lot of links in one section of the page (roughly more than four per paragraph).
  • Avoid including links for the sake of including links.

The primary exception to these rules are choices in favor of user experience. For example, while it is typically not ideal to have several links in close proximity, it may be ideal for user experience in a list of resources.

External links have a great deal of utility for supporting the reader’s experience of your content, and for enhancing the SEO of your domain. Used effectively, external links are part of what holds the web together.