The internet is built on links. Without them, we would have an unorganized mess of disconnected pages that would be difficult to find and navigate.
The original BackRub concept of organizing the hierarchy of pages through a citation system was brilliant. But flawed. Since then, it’s been an ongoing process of trying to perfect that system so that some links have value to count and spammy ones don’t.
What Are External Links?
A link (also known as a backlink) is a hyperlink that will direct a user from one page to another target page when clicked. Applied to a page by adding code like this:
<a href="http://www.domain.com/">Your text (anchor text) goes here</a>
An external link is any hyperlink or backlink, that points to a target page on another domain from the domain it’s published on. It’s external to the host domain.
In SEO terms, the term ‘external link’ usually refers to links that are built on other sites and point back to your domain. These ‘external links’ or backlinks are measured for volume, quality, and relevancy in consideration of how they support the ranking of your page.
An outbound link is also an external link as it points outwards from your domain out to another domain.
- What Are Backlinks?
- Everything You Need to Know about Google PageRank
- How to Do a Backlink Audit in 5 Simple Steps
Internal and External Links
Internal links are hyperlinks between pages on the same domain. They help a user navigate the site and find relevant information they might want to read.
For SEO, Internal links are important as they:
Help link equity to flow around a site so that the value of links isn’t lost on one page.
Help crawlers find a page to encourage crawling and indexing.
Help users navigate through the site on a user journey.
The link ‘value’ or ‘equity’ of an internal link is not measured the same as an external link. Google considers external links to have more value when applied to ranking.
Otherwise, a website could simply build hundreds of internal links to improve ranking. And, that would go against the original concept that links are ‘votes’ from impartial third-parties to support the quality of your site/page.
- Internal Links: A Guide to Building a Strategy that Works
- Advanced Internal Linking with Ross Tavendale
- The Most Common Internal Link Building Mistakes: A SEMrush Study
Nofollow or Follow External Links?
In 2005, Google introduced the nofollow tag as a reaction to comment spam.
“Those links won't get any credit when we rank websites in our search results.”
The nofollow tag is an indication to search engine crawlers that the linked page should not be associated with your page and that it shouldn’t be crawled.
“Use this attribute for cases where you want to link to a page but don’t want to imply any type of endorsement, including passing along ranking credit to another page.”
You can check if a link is nofollow by looking for this tag in the source code:
<a href="http://www.domain.com/" rel="nofollow">Anchor text</a>
Then in 2019, Google updated nofollow to include a new rel=UGC and rel=Sponsored tag to highlight contributions and ‘paid’ for placements.
The biggest change was the update of nofollow to be a hint rather than a directive which would support the belief that some nofollow links on important pages do still pass some link equity.
Hint. It was a directive until the announcement. It's a hint now.— Gary 鯨理／경리 Illyes (@methode) September 11, 2019
Regardless of nofollow or follow, backlinks still have value when placed where they can deliver quality relevant traffic. And this should be considered when building external links.
Are External Links Good For SEO?
The short answer is that external links ARE good for SEO and it’s widely accepted that external links are one of the most important metrics for high-position ranking.
In 2016, Andrey Lipattsev of Google said on record that alongside content, links are one of the top three ranking factors. Go to 30:15 in the video below.
Ammon Johns: We’ve heard that this [links] is the third most important signal contributing to results now. Would it be beneficial to us to know what the first two is? Could webmasters build better sites if they know what the first two is?
Andrey: Yes; I can tell you what they are. It’s content, and links pointing to your site.
Major developments in the knowledge graph, entities, and semantic search have meant that link relevancy is now possibly more important than volume of links. But most SEOs agree that links will always remain a core and important metric for ranking.
External Links: SEO Best Practices
- Relevancy - when building external links, consider the relevancy of the site where the link is coming from. Think about if it’s a natural fit (on a semantic and entity basis) for that page to be linking to your page. A site about cats wouldn’t naturally link to a site about healthcare. Although, a page about cat health might link to a veterinarian or a page about cat health supplements.
- Authority of the linking page - as links are considered to be ‘votes’ to another site based on a concept of academic citations, the more authority a site has, the more value a link will have from that site. Although, PageRank is passed at page level and not site level - so a page on a site might have very little authority compared to the home page.
- Unnatural (or toxic) links - as a hangover from the days of link farms, PBN, and volume spammy link building, many sites built before 2012 have historic harmful backlinks. Post Penguin, this resulted in a raft of manual penalties from Google. A site should review and audit their link profile and file a disavow report for any unnatural links that could potentially be harmful.
- Volume of root domains - relevancy, authority, and quality of links are the most important metrics for external links, but volume does also matter. If you have two sites that both have relevant quality links, then the site with the higher volume is more likely to be ranked highly. When building a backlink profile, go for quality and relevancy over volume.
- Anchor text - post-2012 Penguin, the outing of JC Penney began the change of link building and how anchor test is used. Google does state that anchor text should be descriptive and provide an idea what the page is about, but you should avoid using the same keyword anchor text across all backlinks. Anchor text on external links should be a range of natural keyword variations and natural language pointing to your target page.
- What is SEMrush Domain Authority Score and How It Works
- How to Disavow Links
- Backlink Analysis: How to Spot Quality and Toxic Backlinks
- What is Anchor Text? Everything You Need to Know for SEO