Hidden Links & SEO: How Google Handles Them

Aaron Haynes
Aug 17
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At first, the concept of hidden links might seem pretty simple and straightforward. But then when you come to think of all the parties and elements involved in link building campaigns, the whole thing starts to get a bit confusing.

For instance, you’d probably be curious about who the links are primarily hiding from. Are hidden links meant to remain concealed from Google? Or are we talking about those links that are not directly visible to internet users on the web?

And that’s not all. With web statistics now showing that a majority of the hidden links don’t come from their sites’ webmasters, you could say that even the identity of the publisher may not be that obvious.

Then to top it off, there’s the big question of how it all affects SEO. Do hidden backlinks influence search engine rankings? Or does Google treat them differently from other types of backlinks?

And speaking of which, publishers might also want to know what it all means to them. Do hidden links attract the same SEO points as other outbound links? Or would they be better off without them?

Each of these concerns seems to introduce a different can of worms into the matter. Fortunately for you, though, Loganix is all about exploring such complex stuff in SEO and link building. We’ve compiled this comprehensive guide based on our first-hand experience in link building and hidden links over the years.

By following along, you get to find out what hidden links are, where they are usually published, what they seek to achieve, how they stand to affect your website’s SEO and rankings, how to identify them on your site, plus tools that could help you in handling hidden links.

What Are Hidden Links?

Hidden links is a general term for all the hyperlinks that have been formatted in a manner meant to conceal them from website users.

While regular links can be identified through highlighted anchor text, hidden links are built to purposely avoid direct detection by users through tactics such as

  • Camouflaging linked text with the same font color and formatting as unlinked text.
  • Linking punctuation marks alone instead of placing the URL on openly visible anchor text. You’ll find, for instance, links embedded within hyphens that are often disregarded.
  • Covertly attaching URLs to image files.

To put it all into perspective, Matt Cutts provided this real-life example when he was the head of search quality at Google.

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Excerpt showing hidden links. Source: Matt Cutts

At first glance, all you’d see is a standard article excerpt with two hyperlinks – one on “Roving Mars”, and the other on “Mars Exploration Rover MER”.

As it turns out, however, the paragraph has a third link – one that is purposely disguised to appear like regular text. The culprit is the word “mission”, which strangely enough, happens to hide an outbound link that points to an adult site.

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Hidden link disguised as regular text. Source: Matt Cutts

Matt even went ahead and scrutinized the HTML source code of the web page. The results were as follows…

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Hidden link as viewed through the page source code. Source: Matt Cutts

By breaking down the web page into its technical attributes, you get to see the full structure of the hidden link, plus the formatting used to keep it concealed.

Check out, for instance, this bit of the HTML code:

style=”cursor:text;color:black;text-decoration:none;”

That alone confirms that the anchor text was intentionally set to follow the same style and formatting as the rest of the text. This is what kept the word “mission” from standing out like the other two obvious hyperlinks.

What’s more, the link has been tweaked to maintain the cursor in its natural styling. That means your cursor won’t show a clickable pointer on the hidden link.

And the camouflage doesn’t there. To cover up the link even further, this was added to the code:

onMouseOver=”window.status=’   ‘ ;return true;”

The point of this bit is still to mislead users who happen to hover their mouse cursor over the hidden link. While doing so on a regular hyperlink would show its destination URL on the status bar, this specific hidden link is set to block out all the details.

So, at the end of the day, there’s only one way a typical surfer would discover such a hidden link – by, perhaps unknowingly, clicking on the word “mission”.

When you come to think of it, though, the chances of that ever happening are pretty slim. Web users already have a tendency to dismiss even visible outbound links – that means most hidden links have a near zero chance of success in generating referral traffic.

Ok, if that’s the case, why then would anyone bother building hidden links in the first place?

What’s the purpose of hidden links?

There are two principal reasons why hidden links are still a thing. While most of them happen to target search engines, others have been methodically put together to spam publishers and dupe website visitors.

Here are all the details across their use cases…

#1. Manipulating search engines

Hidden links were initially introduced by black hat SEO practitioners to manipulate search engines. Whereas the styling conceals the links from web visitors, their underlying HTML structure keeps them discoverable by search engines – which is then intended to favorably influence ranking algorithms.

You see, a deep analysis of Google’s search results has proven that, of the more than 200 ranking factors the search engine is currently built on, content and links happen to be the most critical.

In particular, links are seen as some form of endorsement from other web pages – and the resultant ranking gains are based on the domain authority of the referring domains, the number of referring domains, plus the total volume of inbound backlinks.

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The relationship between rankings and the number of referring domains. Source: Backlinko

It’s these qualitative and quantitative linking factors that blackhat SEO practitioners seek to turn to their favor by leveraging hidden links. They spread out the links randomly across multiple websites in the hope of convincing Google that they enjoy an extensive backlink profile.

#2. Spamming websites covertly

And speaking of black hat SEO, the one thing that draws the practitioners to hidden links is their exceptional ability to spam websites covertly. You see, by concealing the links, black hat SEO practitioners get to post them even on third-party websites without the consent or knowledge of the host webmaster.

They are not doing it alone, though. Rather, link spammers are getting help from some of the bad bots that are now controlling over one-fifth of the web traffic. They are specially engineered to gain access to millions of websites, where they proceed to covertly publish hidden backlinks without the knowledge of site owners.

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The percentage of traffic from bad bots. Source: Imperva

In most cases, they tend to target popular sites with active discussion forums. You might find, for instance, a spammer calculatedly publishing hidden links by quoting previous comments left by members in good standing. They usually pick a random comment to reply to, after which they embed hidden links to the quoted text, before finally accompanying it all with unlinked remarks.

As the moderator, therefore, you’d probably review just the added remarks, and then proceed to approve the entire reply post without counterchecking the quoted section.

Bloggers, on the other hand, are often hoodwinked by hidden links placed in simple but hard-to-notice comment characters. For instance – by rushing to approve comments, you stand to miss a random link hidden in a relatively small punctuation mark.

Spammers get even bolder when they stumble upon one of those platforms that give commenters font styling privileges. Your site might come off as funky alright – but link spammers will have a field day adjusting their hyperlinks to look like normal text.

Then at the top of the food chain, we have sophisticated link spammers who double up as website hackers. They first infiltrate your site, and then use the opportunity to covertly add hidden links to your already published articles.

Consider, for instance, the case of the infamous spammers who acquired ownership of a fast-growing WordPress plugin for $15,000.

It might seem like a fairly huge sum at first, but they soon managed to recoup it all by selling linking opportunities across thousands of websites. The plugin itself was running on more than 200,000 sites, giving the spammers an extensive pool of oblivious publishers for their hidden links.

#3. Tricking web visitors into installing malware

Although the vast majority of hidden links target blackhat SEO gains, there’s this category that’s driven by cybercriminals and scammers. They popularly use images and media files to obscure hidden hyperlinks that point to malware, which are then used to launch cyber attacks.

Take, for instance, those email attachments that come embedded with malicious hidden links. They often display a document file or an image, which when clicked on, redirects the recipients to a malware download link. And that’s how businesses, institutions, and individuals ultimately end up as victims of spyware, ransomware, viruses, worms, trojans, and other forms of cyber attacks.

This is more or less the same type of link spam you’ve been encountering from time to time on your Facebook timeline. Spammers typically set them up as image or video clickbait, masking hidden links that are meant to compromise user accounts.

So huge has the problem grown, in fact, that 30% of the top 20 most widely viewed links on Facebook are driven by such types of spam. That translates to a whopping 112.2 million views every three months.

Consider, for instance, this hidden link that had garnered over 12.3 million impressions by the time it was flagged up and brought down by Facebook. During the entire period, it kept redirecting Facebook users to a website called “heaveemotions.com”, from where individuals would be misled into installing malware.

What Google thinks – The impact of hidden links on SEO

In case you’re wondering, the answer is yes – hidden links have an impact on SEO.

But, get this. It’s not a positive one.

You see, Google is not the type to take such black hat campaigns lying down. The search engine has upgraded its crawlers to the point of accurately picking out hidden links – along with many other forms of spammy links –  and separating them from regular backlinks.

Then as it rewards natural high-quality backlinks with better rankings, it goes on to penalize and potentially blacklist both publishers plus beneficiaries of spammy hidden links.

This has been the case since 2009, when Google filed for a patent on its internal system for identifying hidden text and hidden links in a document. The patent, which is named “Systems and methods for detecting hidden text and hidden linkswas later awarded in 2013, granting the company yet another baseline for fine-tuning its efforts against black hat link building tactics.

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Google’s patent on discovering hidden text and hidden links. Source: USPTO

You can check out Google’s sentiments on the matter from its Webmaster Guidelines on hidden text and links. It clarifies that hidden text and hidden links intended to deviously influence search rankings are in violation of the accepted SEO principles.

Therefore, if there’s any SEO impact you’ll be seeing from hidden links, it’s less search visibility courtesy of the possible spam penalties.

This applies even when you’re completely unaware of the existence of hidden links on your website. Google will still penalize you for trying to compromise the quality and sanctity of its search ranking system.

It’s worth noting, however, that the penalties might not be that severe for hidden internal links. This was revealed in 2021 by Google’s Webmaster Trends Analyst John Muller, who additionally clarified that even cloaking is exempted from the penalties.

Now, for the sake of clarity, cloaking is the practice of using CSS to display one version of site content and URLs to Google, while your site visitors get a different composition.

That said, the best approach overall would be maintaining outbound and inbound links that are both human-readable and machine-readable. Website users and search engines should be able to easily identify and interpret all the backlinks pointing to your site, plus the corresponding outbound links published on your web pages.

How To Handle Hidden Links For Maximum SEO Benefits

As we’ve seen from the tactics used by spammers, hidden links is an SEO issue that is strongly tied to your website security. So to protect yourself accordingly, you need strategies for not only identifying and removing potential hidden links, but also safeguarding the security of your website.

Here are the step-by-step proactive and reactive measures that’ll help you achieve all that…

#1. Find hidden links through an on-site link audit

The first step entails finding all the possible hidden links that might be holding back your website’s SEO. At least then, you’ll be able to figure out what needs to be removed to save your site from possible penalties, restore a healthy link profile, and ultimately regain your rightful search rankings.

That said, there are multiple ways to discover hidden links on your website. You could either do it manually from one page to another, or possibly bring in a specialized link auditing tool for automated crawling and analysis.

The manual process itself is simple enough for both novices and technically-skilled webmasters. Here are the steps you should follow:

  • Launch a standard web browser like Google Chrome or Mozilla Firefox, and then use it to access any of your web pages.
  • Hit the right-click on a random section of the page and choose “View Page Source” from the list of options.
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Page source window

  • You could, otherwise, simply use the equivalent keyboard shortcut command by hitting CTRL+U.
  • Whichever you choose, the screen will immediately display the underlying source code of the web page. It might seem a bit technical at first, but don’t sweat it – you won’t be doing any coding here.
  • You just need to highlight the links based on their basic HTML attributes. All it takes is opening the browser’s search tool through “CTRL+F”, after which you enter the link attribute “href”, before finally proceeding with the search process.
  • The system will then highlight all the links identified on the page. This is where you carefully scrutinize each one by its context, placement, formatting, and anchor text.
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Searching for links on the page source window.

  • You’ll eventually be able to pick out all the odd ones that look and feel like hidden links.
  • Once you’re done with the first page, you should repeat the process across all your web pages. And while you’re at it, remember to keep following up on each suspected hidden link instance. You can remove them from your CMS dashboard by simply unlinking or deleting the text.

If you’d, otherwise, prefer performing the process with a link auditing tool, we’d recommend proceeding with simple but reliable solutions such as Link Grabber, Inspect Dev Tool, Web Developer, or Dr. Link Check.

Link Grabber is particularly straightforward, as it comes in form of a free Chrome extension. It’s built to extract hyperlinks from HTML pages, display them as a list, and then help you with the analysis.

A quick scan of the resultant report should reveal all the unusual links appearing on your web page. Then for increased accuracy, you could filter them out by substring match.

#2. Block link spammers with antispam plugins and extensions

Once you’ve managed to find and remove all the hidden links from your site, you can embark on the protective strategies. The point here is to seal all the loopholes that would, otherwise, grant link spammers easy access to your website.

You can start by setting up a fully automated antispam system that’s capable of discerning genuinely organic content from spammy submissions. Plus, it ought to operate with the precision of a hawk – watchful enough to flag up all the spamming attempts, but methodical enough to maintain a clean slate devoid of false positives.

If you happen to be running your site on any of the biggest CMS or forum management platforms, one tool that excellently fits the role is Akismet. This is an exceedingly popular antispam plugin for WordPress, Joomla, Drupal, Discourse, Elixir, VBulletin, SMF, phpBB, Moodle, Mediawiki, and Perch.

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Sample spam blocking stats from Akismet. Source: Akismet

You can count on it to block out not only spammy comments, but also spammy contact form submissions, spammy site edits, plus signups from spammy users.

#3. Set up a strong web application firewall

While your antispam plugin continues to protect your site from spammy commenters and link building bots, you should have a complementary security shield warding off possible infiltrations that could covertly inject hidden links.

This is where you bring in a firewall that’s capable of monitoring traffic 24/7, detecting possible system attacks, blocking off hacking attempts, and mitigating vulnerabilities – all the while maintaining a seamless flow of benign traffic.

You could, for instance, consider riding on a tried and tested web application firewall (WAF) such as Cloudflare WAF, AWS WAF, Barracuda WAF, or Citrix WAF.

All these can be counted on when it comes to filtering, securing, tracking, and overseeing HTTP traffic between the internet and your selected web application.

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Managing web application firewall with Amazon Web Services WAF

Put simply, your WAF system will keep tabs on all the HTTP requests, as well as assess all the accompanying parameters to meticulously separate malicious signals from authentic traffic.

Consequently, you’ll be able to avoid all possible hidden links that could arise from SQL injection, file inclusion, cross-site scripting, and cross-site forgery, among other types of intrusion techniques.

Over To You – How To Manage The Whole Process

Hidden links have shown that while they principally target search engines and their invisibility is experienced largely by site users, the biggest victims are always site owners, publishers, and webmasters.

You see, unlike regular spammy links, hidden links never announce their presence. You won’t see them coming, and neither will you be notified when they take over your site. Everything always seems to be proceeding fine until Google finally drops the bomb on you.

That’s when you find yourself incurring penalties and declining fast in the search rankings. You might protest alright – but, as we’ve said, Google is not really known for clemency. All spammy publishers are treated as blackhat SEO practitioners out to manipulate the Google PageRank algorithm.

So, even though you understand the SEO implication of hidden links and may not be looking to build them, there’s always the possibility that they might be the ones coming over to your side. This is why, in fact, we call them the boomerang of link building – they have a way of always coming around whether you’re interested or not.

And the worst thing is, they tend to invite the wrong kind of attention from Google. One that could potentially negate all the gains you’ve made from your SEO and digital marketing campaigns.

It’s because of all these unavoidable risks that we’ve been coming in to assist all types of businesses with their link building and SEO campaigns. We understand that it can be overwhelmingly difficult to juggle between managing the business, building content, networking with other publishers, engaging audiences, coordinating PPC ads, creating links, and catching up with competitors’ rankings – all the while auditing your entire site to resolve hidden links and other SEO issues that might be negatively affecting your rankings.

Ok, that’s no easy feat. But, while we totally applaud you for all the hard work, we also acknowledge that it’s not quite optimal for today’s exceedingly competitive search rankings. If you hope to outshine your competitors on Google, then it’s high time you took a more strategic approach.

Think about how well things would pan out if you focused all your efforts on managing the business – while, on the other hand, the seasoned SEO experts at Loganix handled your link building, site audits, PPC campaigns, blog writing, local SEO, press releases, etc.

Book your strategy call today and let’s make it a reality.

Written by Aaron Haynes on August 17, 2022

CEO and partner at Loganix, I believe in taking what you do best and sharing it with the world in the most transparent and powerful way possible. If I am not running the business, I am neck deep in client SEO.

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