Link building is one of the most important parts of your SEO strategy. High-quality backlinks are among the most critical factors search engines like Google use to determine where to rank your content for specific keywords.
It’s also the hardest. And it takes the longest.
Like anything else that’s valuable yet difficult, there will always be someone who wants to cheat.
Link spam is one way people try to cheat the system.
What is link spam?
Link spam refers to the practice of creating low-quality or irrelevant backlinks to a website in an attempt to manipulate search engine rankings. Also called link schemes, these unnatural backlinks can come from paid services, automated programs, or manual submissions.
The idea behind link spam is simple: the more links a website has, the more popular and authoritative it must be. Therefore, spamming out-of-context links all over the internet will eventually make search engine algorithms think your site is a reliable and trustworthy source, boosting your ranking.
Here are a few examples according to Google’s link spam policy:
- Buying links to or selling links on your site
- Excessive link exchanges (key word: excessive)
- Automated link building programs
- Putting links as a requirement in your Terms of Service agreement
- Adding optimized, keyword-rich links in forums
- Widely distributed links in footers, widgets, and site templates — for instance, hard-coding a link to your site in every copy of a WordPress template you give away for free
- “Followed” ad links that pass PageRank
- Manipulative or sneaky redirects
As Google continues to develop its algorithm, it becomes more sophisticated and better at identifying these tactics.
The result? Potential penalties in the form of lower ranking and even removal from search engine results pages (SERPs).
Does link spamming still work?
Meh. Not really.
There was a time when link spamming could get you high rankings with little effort.
There was also a time when toxic backlinks could really hurt your site.
Google’s Penguin Algorithm update was first introduced in 2012 to crack down on spammy link building practices. And subsequent updates (like the 2022 link spam update) have only made it more difficult to succeed with link spamming.
Penguin assesses links based on…
- Context (relevance to the page and topic it’s linking from)
- Quality (in terms of trust, authority, and popularity, plus E-E-A-T signals)
- Quantity (natural-looking link profile that gradually increases over time)
….none of which are achievable through link spamming practices.
Do I need to worry about spammy links?
Meh. Not really.
According to Google, Penguin automatically ignores links from spammy sites. And content that gives out too many spammy links is devalued on a case-by-case basis (as opposed to a whole website).
So, link spam won’t benefit (or necessarily hurt) the site receiving the links. Nor will it help the efforts of whoever’s creating and distributing these links.
Beyond the fact that it’s literally a waste of time, it’s worth mentioning link spamming tactics are shady black hat techniques that go against Google’s Webmaster Guidelines.
Even if spammy links themselves don’t hurt your site (since Google ignores them), actively and intentionally practicing these tactics can eventually lead you to huge penalties that harm your site and reduce your search visibility.
If you’re serious about growing a legitimate business, don’t do it. 100% chance you’ll regret it.
Types of link spam to watch out for:
Cleansing domain is known colloquially as “301.” It’s a link manipulation tactic where spammers exploit a site’s 301 redirects settings to improve the search engine ranking of their own sites.
The basic idea is simple.
- When a spammer gets a link on another site, they point it at a site that no longer exists.
- Then, when the spammer 301 redirects the expired domain to their own website (using web server settings or .htaccess file), all the “link juice” gets passed on to their site.
The intention is to make it look like the link came naturally from a legitimate site, without the spammer having to put in any real effort.
This technique is known as “cleansing domain” because spammers use expired domains that have been de-indexed from Google for link spamming to cover their tracks.
Shady site owners might hide spam links to avoid messing up their user experience or ruining their blog content.
- Setting your link color to match your background color
- Placing hidden links behind pictures or text
- Adding links to certain words that are invisible
- Hiding links in the site’s code, so only an algorithm can see it
The idea here is that a site can appear normal on the surface, but a search engine algorithm will still see the hidden links and give them credit.
Private blog networks (PBNs)
People who don’t want to invest in legitimate link building (think, people buying $5 links off Fiverr) try building links through link farming and PBNs.
PBNs are private networks of sites that exist solely to link to one another. They work like this:
- A group of people creates multiple sites (e.g., blogs, forums) to link to one another.
- Each site in the PBN can link back to any other site in the network, or your website.
- These links don’t have to appear super prominent or relevant; they’re just there to pass on “link juice” to one another.
More often than not, these sites are low-quality, with thin or duplicate content (read: no real value for users).
PBNs rarely get discovered as a whole because these types of networks are usually quite good at masking their footprints, and Google only has so much resources. But Google does catch onto individual websites that belong to PBNs.
A link farm is a website created specifically to link to other sites to manipulate search results. Often, these are low-quality websites that contain little more than lists of unrelated links.
Private blog networks are one example of link farms. Others include:
- Forum or comment spam — Commenting on forums with links to your site
- Blogspam — Leaving comments on other blogs (often spun or scraped) with links back to your site
- Wiki spam — Posting self-serving and meaningless content on online wikis that allow them (and the worst of these can really be spamdexing)
- Directory/article submission — Submitting articles or creating directories containing nothing but low-quality content or links to random businesses
- RSS blog feed directories — Creating blog directories that pull in RSS feed content from other sites with low-quality links
Most of the blog sites that look like this are link farms, for example:
They always have content with a few random external links, tons of ads, and stock images for nearly every piece of content.
And none of the content seems to be interrelated. All random topics.
The content is normally 400-500 words. And you can spot the link from a mile away.
Back in the day, there were even experts who used this strategy.
Basically, you pay a site owner to link to your site from every page on their site (normally in the footer).
These links don’t necessarily have to be spammy. Some are legitimate acknowledgments and endorsements. Or, you may have a partner site you want your customers to know about.
But, since they’re easy to implement and can sometimes be used for link spam, Google has scaled back their impact (both positive and negative).
Nofollow backlinks aren’t inherently bad. They’re actually a crucial part of a healthy link profile.
The problem is when you have too many nofollow links. Since links from forums, social media, directories, and commenting platforms usually include a nofollow tag, you need to be careful when building these links so your backlink profile doesn’t look too unnatural.
Vetting potential sites for link building
If you’re getting links from a bunch of spammy sites, you won’t get as much value from each link. And if you go full black hat, you’ll probably get hit with a penalty at some point.
If this happens, you’ll see it in Google Search Console under “Security and Manual Actions.” And, you’ll see a huge drop in organic traffic and search rankings.
In extreme cases, you might even be removed from SERPs.
So, how impactful your link building efforts are largely depends on whether you’re building high-quality, relevant links that provide value to your site’s visitors.
Here’s a basic rundown of how I use Ahrefs to vet sites for guest posting and link placement opportunities.
1. Set your evaluation criteria.
Before you build a relationship with a website owner, you need to know what you’re looking for. There are three factors you have to consider when looking for prospects:
- Relevance — How pertinent is this site to your industry and keywords?
- Domain Rating (DR) — How authoritative is this website on a scale from 0 to 100?
- Organic traffic — How many unique visitors does this site get from organic search?
You can find Domain Rating and organic traffic on the first dashboard as soon as you copy/paste or a site’s domain into Site Explorer.
You should also look at these metrics over time. For example, this website’s traffic continues to tank after every Google algorithm update.
For relevance, this’ll depend entirely on what you’re looking for. You don’t need every link to come from a site in your niche (a site like the New York Times would obviously provide a ton of value), but total relevance should be a factor when evaluating link opportunities.
Normally, I go for sites with the following criteria:
- Relevance: Niche-relevant or, at the very least, relevant to my target audience
- Domain Rating: DR 40+
- Organic traffic: 1,000+ traffic per month
- Traffic value: $1,000+
2. Get rid of questionable sites.
Link spammers often target sites that don’t have a ton of editorial oversight. And, no surprise, many link spammers also run sites with little editorial oversight.
Take this site for example:
None of the topics seem contextually relevant to each other. So, even if a few are similar to your business, you won’t get as much value from them.
When you open their content, you can tell it’s not the most high-quality stuff. And you can see exactly where they threw in a clunky, over-optimized keyword with anchor text.
And yes, they took a nosedive after Google’s 2022 Link Spam update.
3. Dig deeper into their link profile.
It’s normally pretty easy to see whether a site sucks on the surface. But, to really get a sense of their quality, you have to go deeper. Here’s what I do to vet a site:
- Check their inbound links (the number of backlinks pointing to their site) and see if they have a healthy backlink profile
- Check the types of sites linking to the target site (If I see a bunch of link farms and foreign language sites, the site’s probably spammy)
- See how often their content is shared on social media.
You can use Ahrefs for this stuff, too. Just go to Site Explorer and enter your target domain.
Then, go to Backlink profile > Referring domains and scroll through their backlinks.
If there are a lot of high-quality sites in their backlink profile, they should be good to go.
4. Check outgoing links.
It’s possible for a site to have a decent DR and solid link profile while still giving out a lot of low-quality links.
This site’s DR and link profile are quite good:
But when you check one of their homepages, you see there’s a bunch of hidden links to gambling websites:
Looks like this site has a propensity for linking out to low-quality sites in their content (which isn’t very high-quality itself). And they aren’t shy about using weird, over-optimized anchor text.
5. Look at competitors’ links.
It’s normally pretty easy to see whether a site sucks on the surface. But, to really get a sense of their quality, you have to go deeper.
You can do this with Ahrefs’ Link Intersect tool. Just select your site plus a few competitors and the tool will show all of the links that point to your competition but not you.
Usually, if a competitor has a link from a site and I don’t, it’s because they have a better relationship than me or they’ve created more value for the site owner.
So, I’ll check out how those links were acquired. If it’s from guest posting, I might try to replicate that approach.
If it’s because of something their product does (like an embeddable graphic), then I know I can’t use their backlink as a benchmark.
If the link’s from a press piece or because of an event, then it’s worth evaluating how likely it is that I can replicate this event, too.
Avoid link spam with proper vetting
When it comes to link building, quantity is obviously important.
But you in no way should skimp on quality. That’ll only lead to a shaky foundation at best, and a burned site at worst.
And, if you’re hiring an agency to handle things for you, ask them about their vetting criteria as well.
You already know ours is rock-solid.