The tags nofollow and noopener aren’t interchangeable.
Here’s how they differ:
The tag was initially introduced by Google in 2005 to fight comment spam on websites. The objective was to ensure that any link appearing in the comments section isn’t able to pass PageRank (PR) or SEO value to the target webpage. In other words, the tag is used to tell search engines to “not follow that specific URL” or “ignore the target webpage.”
Here’s how the rel=nofollow tag appears in the WordPress Editor:
<a href="http://awebsite.com" rel="nofollow">Any Website</a>
Today, you’d see website owners using the rel=nofollow tag on a variety of webpages. For instance, it can be used in a blog post to tell Google, Bing and other search engines not to pass any value to a specific link.
This tag is used to tell search engines that the target URL should not receive a reference to the previous URL. It mainly instructs browsers not to pass the “HTTP referrer header” if the visitor clicks the linked URL, which prevents the newly opened webpage from gaining the ability to control the webpage that passed the traffic.
Here’s how the rel=noopener tag appears in the WordPress Editor:
<a href="http://awebsite.com" rel="noopener">Any Website</a>
Unlike rel=nofollow, the rel=noopener tag will still pass SEO value to the linked URL. Simply put, it has an impact on the browser level and doesn’t affect SEO.
Note: Another term for rel=noopener is rel=noreferrer. You can use either of these to prevent search engines from passing browser-related information about your website.
It makes sense to use the rel=nofollow tag when:
You link to a website that requires a registration or login.
You link to a website that you don’t want to vouch for.
You link to a website with whom you have an affiliate partnership with. That’s because passing SEO value to your affiliate partners could get you penalized.
It makes sense to use the rel=noopener tag when:
You link to a website that is owned by an anonymous person.
You link to a website that has been a victim of a phishing attack in the past.
You link to a website that has weak or minimum security.
The rel=nofollow tag will have null effect on the SEO of the website you link to, while the rel=noopener tag would still pass SEO value.