Updated April 7, 2016
When a search engine robot (“bot”) lands on a page on your site, it crawls through and reads the text on that page. This is the way it figures out what your page is about, a vital step in SEO.
Once it knows what your page is about, it can index your page and show it in search results when people are looking for that type of content.
But sometimes it’s not so straightfoward.
What about links?
As the bot crawls through your page and comes to a link, it follows that link and crawls the page you linked to as well. The link is like a door to that other page and the search bot goes through the door (link) and reads the next site too.
Whenever you link to another page on the internet, you are basically telling the search engine, “Hey search engine, here’s a page I like and I think you should go read it too.”
It’s like you’re giving the linked page a thumbs up. It’s also referred to as “passing PageRank.” In other words, you’re spreading Google love and “voting” for that linked page.
And the search engine says, “Hey, thanks for the suggestion! I’m always looking for more sites others like, so I’ll be sure to check it out.” Then off it goes through the door. It crawls that site and adds it to its arsenal of good sites to put in search results.
This is what makes the internet go round. (Or at least search.)
But not all links should get a thumbs up from you
There are times when you don’t want to, or shouldn’t, give a thumb’s up to another page when linking to them. Google has a good rundown, but I’ll give you the gist:
- Maybe you’re linking to a site you can’t exactly vouch for so you’re not entirely comfortable casting a favorable vote for it.
- Maybe you’re linking to a forum or some other site that requires registration or a login. Because bots can’t register or log in, it’s not really helpful for them to visit that site. In that case, it’d be better for that bot to stay on your site and explore your site a little more.
- Maybe you’re linking to a site that is somehow advertising-related or a site from which you’ll make money, like an affiliate link or a sponsor. Search engines are interested in keeping their search results clean and not influenced by paid relationships, so this isn’t a good time to give a thumbs up either. Update: Google has written more about this and reminds site owners that passing PageRank to sites with whom you have this sort of relationship (including receiving any free product) goes against their terms of service. Also, do not forget to disclose your relationship in those posts as well. I wrote more about that here.
Enter the nofollow tag
So, what’s a site owner to do? Is there a way to link (so your readers can check it out) but not give a “thumb’s up” to the search engines? Why yes, yes there is.
Use the nofollow tag.
The nofollow tag on a link tells a search engine not to follow that link. Essentially, you are closing the door to that link so the bots don’t go there.
Always use the nofollow tag when:
- You link to a site you don’t want to “vote” for or can’t vouch for.
- You link to a site that requires a login or registration.
- You use an affiliate link or are linking to a sponsor site or another site with whom you have a some sort of paid relationship.
How to add the nofollow tag to a link
Step 1: Write your page or post.
Step 2: Add a link to your text as you normally would. (In WordPress, simply highlight the text you want to be the link and click the link icon at the top of the post input window.)
Step 3: Switch to HTML mode. (This is easily done in WordPress by switching from the “Visual” tab to the “Text” tab at the top of your post window.)
Step 4: Find your link in the HTML. A link looks like this:
<a href="http://somelink.com">Some Link</a>
Step 5: Now, add the tag rel=”nofollow” within the <a> tag like so (bolded here so you can see it):
<a href="http://somelink.com" rel="nofollow">Some Link</a>
That’s it! That link is now a nofollow link.
Is there an easier way to add a nofollow tag to links?
Well, yes, in WordPress you can find plugins that allow you to do it quickly. However, as you may know, I don’t recommend using a plugin to do so. I explain why in my tips about plugins.