Link building is a complicated art form with many different tactics and approaches.
Despite being one of the most mature processes in SEO, there’s still much disagreement about what makes a “bad” or “good” link building strategy, including effectiveness vs. risk, and what tactics Google can detect or punish a website for.
This post will help you determine what to avoid when link building or vetting the tactics of a new service provider.
I’m not going to claim to put any disagreements to rest, and if you’re a particularly experiment-minded SEO you might find this post a little on the conservative side.
As with all things in the industry, there’s inconsistency between what Google says and what works, and everyone benefits from those who experiment and push boundaries.
But I’m taking a conservative approach that follows Google’s guidelines closely for two core reasons:
This post is for readers looking for reliable and sustainable strategies. I don’t advise that you use experimental or high-risk tactics when it comes to link building if you don’t already know what you’re doing and what the risks are.
You should take the guidelines as a statement of intent, not absolute or current truth. Even if a link building tactic that goes against Google’s guidelines works now, there is reason to believe that Google intends to address it.
How To Avoid Toxic SEO Links
1. Buying Or Selling Links2. Link Exchange Agreements3. Private Blog Networks4. Unnatural Links From Forums, Blog Comments, And Other User-Generated Content5. Automated Link Syndication6. Links To Your Site Vs. Links From Your Site
Types Of Unnatural Links
A an unnatural link is any link that is created for the purposes of manipulating search engines or that violates Google’s spam policies.
The following are some of the most common types of unnatural links.
Buying Or Selling Links
There is nothing fundamentally wrong with paying for a link or exchanging some kind of product or service for a link as long as the nature of the relationship is disclosed and the links are not for SEO purposes.
Buying, exchanging, or trading for links for SEO is the problem. Links for SEO are supposed to be a choice influenced only by the content on the page.
If your content is highly valued and people choose to link to it for that reason, then you deserve SEO benefits.
When you enter money or value exchanges into that dynamic, it breaks the ideal purpose of SEO links and introduces a high potential for manipulation. In such cases, Google requires marking the link as rel=nofollow or rel=sponsored so that the links do not pass SEO value. As long as you or the parties linking to you do this, for the most part, there’s no problem.
Here is an example of implementing nofollow and sponsored attributes:
<a href=”https://example.com” rel=”nofollow”>read our guide</a>
<a href=”https://example.com” rel=”sponsored”>read our guide</a>
Here are some ways that buying or selling links can fall afoul of Google’s spam policies:
Text advertisements with links that pass SEO signals because they haven’t been identified with “nofollow” or “sponsored.”
Paying for articles that include links that pass SEO signals.
Another way to buy links is to pay someone to create them for you. In this case, a service provider does that work of creating assets, reaching out to acquire links, or both. As long as this service provider doesn’t engage in shady tactics of their own and doesn’t give you links on domains that they own, this is totally fine.
Keep in mind that the “buying” and “selling” definitions are not limited to an exchange of currency.
It describes any kind of relationship where something is exchanged for a link, like a product.
As Matt Cutts explained in 2014, Google aligns pretty closely with the FTC on what it understands to be a “material connection” between a link provider and link recipient:
If a party receives enough value to reasonably change their behavior, a material connection must be disclosed.
A pen or a t-shirt likely won’t change behavior (unless received for the explicit purpose of reviewing / linking to it).
A direct payment for a link, a gift card, or a product with a high dollar value likely changes behavior and incentivizes a link.
An item loaned has different implications than an item given.
Consider the intended audience: if you’re giving things away for reasons other than to acquire links (for example as part of a conference attendance gift package), then disclosure might be necessary, but it might not be strictly necessary to ask all those people to mark links as sponsored if they choose to talk about it.
Consider whether a link relationship would be surprising: it makes sense that a movie reviewer might see a movie for free. It makes less sense that a tech reported would get to keep a laptop they’re reporting about without disclosure.
Link Exchange Agreements
Link exchanges are similar to buying links because they involve an exchange of value.
Mutual linking happens often, and when it occurs organically, it’s no problem. It makes perfect sense for some websites to link back and forth.
But you need to watch out for any kind of agreement. “Link for link” is a no-go, and if you do it often enough, it can become easy to spot.
The thing about links is that any time you give or get a link for a reason other than the value and relevance of the link itself, it’s easy to spot – likely easier than you think.
The occasional bit of back rubbing isn’t a big deal. When given a few different choices of websites to reference, it makes sense that people would choose those they already know or have existing relationships with.
That’s generally fine. The problem comes when you enter into specific agreements: You link to me, and I’ll link to you.
The video below explains the difference between a link that’s an editorial choice and a link that’s based on an agreement.
Private Blog Networks
Private blog networks (PBNs) are networks of sites created to artificially inflate the rankings of one specific central website.
Basically, one entity controls an entire network of websites and can use a few different specific linking methods to manipulate to pass authority and SEO value around.
This network can then be used to artificially inflate the rankings of other websites by linking out to them.
In order for this tactic to work, all the websites need to have relationships or be owned by the same entity.
This is a pretty clear violation of Google’s guidelines, and it’s also pretty easy to spot.
Sites that are part of these networks can be penalized, and if you’re a little too lax with user-generated content on your site, you could find yourself accidentally becoming one.
If you accept any kind of content from external parties, scrutinize it carefully, especially links. Skip down to “How To Spot Shady Links” to find out more.
Unnatural Links From Forums, Blog Comments, And Other User-Generated Content
User-generated content is tricky when it comes to links. Ideally, a random person loves your content so much that they use you as a reference. Not so ideal is faking it.
Comments, forums, blogs, guestbooks, and even sites like Reddit might be tempting sources for links, and in the right context, they can absolutely be part of a healthy backlink profile. You can even link to yourself if you’re genuinely engaging in a relevant discussion. Google doesn’t consider all comment links and UGC links to be spam.
However, it’s a bad idea to try and engineer these links as part of a mass strategy.
The first thing to keep in mind is that many user-generated content (UGC) websites have blanket nofollow attributes on outgoing links. It’s an old tactic, so many high-quality communities moderate UGC heavily. This means that doing this effectively requires effort. The big question to ask yourself is: does the comment add genuine value to the community?
Most commonly, people execute these links unnaturally using bots to post automatically. Generally, automated posting using bots isn’t exactly valuable, and you’ll be flagged and moderated out of those communities.
Automated Link Syndication
There are tons of ways to automate links, but Google considers automating links at scale to be spam.
There are plenty of ways to safely automate your content processes, but we aren’t talking about that. We’re talking about using automation to post content externally from your website purely to acquire SEO links.
From automated article spinners to bots that will post comments and social media posts, if you’re intentionally building links “at scale,” then the chances are high that you’re building toxic links.
This could look like an automated press release or directory posting. It could look like low-quality article directories, which are often filled with spammy content that is widely distributed.
Generative AI has enabled new forms of automation for links and content, so it’s important to consider the overall principles in Google’s and the FTC guidelines when you evaluate novel functions and strategies.
Links In Distributed Widgets
People sometimes engage in automated link building by adding links to widgets distributed to multiple websites. Google clarified its stance on this and provided examples of manipulative widgets.
This kind of link building is pretty easy to spot, and it’s pretty clear that these types of links don’t add value.