External link: A link from your site to a page on a different domain. Seen from the site it points at, the same link is a backlink.
Why they matter to your own site
Linking out is how you show your working. A personal-finance post that cites the tax authority’s own page, or a recipe that credits the cookbook it adapted, is more useful to the reader and easier to trust. There is no evidence that linking to good sources costs you rankings, and plenty of reason to think it helps readers.
When to qualify them
Google asks you to label certain outbound links with a rel value. Its guidance on qualifying outbound links uses rel="sponsored" for paid or affiliate links, rel="ugc" for links in comments and forum posts, and rel="nofollow" when neither fits but you do not want to vouch for the page. Paid links without one of these are treated as link spam. An outdoor-gear review site with affiliate links to retailers should mark every one of them sponsored; WordPress affiliate plugins can usually do this automatically.
How to check on WordPress
- A crawler with external links enabled lists every outbound link, its status code and its
relattributes. - Look for external broken links — other sites move pages too — and for affiliate links missing
sponsored. - Rank Math and Yoast SEO both show an external link count per post.
Making every external link nofollow does not keep ranking value on your site. It only withholds your endorsement from sources you chose to cite. Use nofollow where you mean it.
How outbound links fit alongside internal ones is covered in the internal linking strategy guide.