Stumbled on an interesting blackhat SEO link building strategy this week that those tending towards the whitehat SEO arena should steer well clear of.
I’ve been testing free SSL certificates from Letsencrypt and had signed up to their forum for support.
Letsencrypt uses the Discourse Forum Software from discourse.org. After 15+ years of SEO research I find it difficult to visit a website without having a look at the HTML code behind the curtain and as I visited the Discourse Forum I viewed source (Right Click the webpage, “View Page Source”) and found what appeared to be a semi-hidden link within a noscript tag.
That got my SEO juices flowing: that sounded much better in my head!!!
For the record the people behind the Letsencrypt site (and other Discourse Forum script users) haven’t done anything blackhat, they like many other unsuspecting webmasters have installed the Discourse Forum script to run their forum: it’s the people behind discourse.org who are using blackhat SEO link building techniques to build quick backlinks to their sites.
What’s a Semi-Hidden Link Within a Noscript Tag?
In HTML code terms you’ll see something like this in the code source:
Flash based content is a good example.
When I viewed source of a Discourse Forum webpage I found this:
Normally I’d confirm the hidden text link by viewing the Googlecache of a webpage, but I got lazy and assumed it would be in the cache and informed the Letsencrypt forum they have a hidden link and should fix it ASAP: Hidden Link to Discource.org, Potential SEO Issue (I was in that much of a rush I also spelled Discourse wrong, Doh!).
Eventually I checked the Googlecache and here’s where it got interesting, we now go into the hidden realms of blackhat SEO cloaking techniques.
What is Blackhat SEO Link Cloaking?
When search engine spiders like Googlebot visit websites they use specific user-agents, webmasters can use Googlebots user-agent to serve Google content NOT served to other visitors. If you are contemplating using blackhat SEO link cloaking, consider when caught your site will receive a Google penalty!
For example you might have links in an image-map, image-map links can not be indexed by Google, so it would be acceptable to serve Googlebot those links in another format. General visitors see the links in an image-map, Googlebot sees them as text links or standard image links (a clickable image link). As long as a general visitor and Google sees pretty much the same content AND you aren’t gaming Google, it’s acceptable to use cloaking.
This is where what discourse.org are doing gets interesting.
What Discourse are doing here is checking for the Googlebot user-agent and serving different content to Googlebot.
Potentially a Google penalty incurring SEO issue.
It’s quite clever blackhat SEO setup that’s not easy to spot.
Googlebot gets a sitewide text link to the Discourse home page, as it’s not within a noscript tag** Googlebot will definitely pass full SEO benefit through this link.
** Some SEO experts argue links within noscript tags won’t pass full SEO link benefit because they are hidden to most users: from an SEO perspective it’s difficult to test, so best to avoid adding important links within noscript tags if they aren’t available in standard body text.
That’s 1.7 million webpages using that exact phrase, that’s probably 1.7 million hidden backlinks, some serious link benefit they are stealing from their forum software users! There’s an SEO market for buying/selling links, it could cost hundreds of thousands of dollars to buy this number of text links from quality websites and they are getting them for free.
If a webmaster notices the above links in the Googlecache say and check out their forum (viewing source) they find the link within the noscript tag, which though not a particularly ethical way to gain a link it does at first viewing match the Googlecache so doesn’t look like cloaking.
In my opinion this is a deliberate blackhat SEO attempt to hide the backlinks from forum owners. In comparison phpBB forum software has a similar powered by link, but it’s visible to everyone (forum visitors and Google) and there’s loads of articles online about how to remove the phpBB forum links. By hiding the Discourse.org links this way only the most SEO knowledgeable webmasters are going to notice these text links and look to remove them.
Interestingly when you view the message linked to the commit for this link at Github it mentions SEO:
Put the ‘Powered by Discourse…’ message shown to crawlers and no-js visitors in a footer element so that SEO something something.
It would appear the links are added for SEO reasons, what are the SEO reasons?
Discourse.org Response to Being Caught Using Blackhat SEO Techniques
I signed up to the Discourse forum and made a post titled “Cloaked Link to Discourse.org Within Your Forum Software: Potential SEO Issue”. I explained the above issue etc… and one of the co-founders (Jeff Atwood) responded trying to justify the blackhat SEO links, to which I gave a follow up: few hours later the forum topic was deleted and my Discourse forum account was deleted :-)
Fortunately I always keep a copy of everything I post to forums etc… (not my first rodeo :-)) and have posted the deleted forum post as a comment below and took screenshots of the forum posts GoogleCache.
Update: Made an error below, the Discourse software has a feature where links posted by trusted forum members are NOT nofollow. My mistake was seeing links to discourse.org lacking nofollow which were posted by a trusted forum member (pure coincidence) and jumping to the wrong conclusion it was another blackhat SEO link building technique. I was wrong, everything within the “More Blackhat SEO Techniques Used by Discourse Forum Software” section below is wrong.
Thanks to PFG (via a comment) for clarifying why some links lacked rel=”nofollow” tags. I’ve kept the section because even though I was wrong it’s a possible blackhat SEO technique to look out for: if I were into blackhat SEO techniques I could use it with the WordPress SEO themes and SEO plugins I release.
More Blackhat SEO Techniques Used by Discourse Forum Software
It gets better, as I was writing this blackhat SEO tutorial I noticed when viewing source of the Googlecache of Discourse forum posts links to discourse.org are NOT rel=”nofollow”!
Like most forum software scripts, Discourse adds a rel=”nofollow” tag to links added by forum users, this is to stop forum spammers from benefiting SEO wise from the links: Google ignores links with the nofollow tag and passes no SEO benefit.
It would appear Discourse have added an exception for links to their own sites!!!
WOW, now technically not blackhat SEO per se, but you have to admit it’s very shady and not particularly ethical especially when taking into account the 1.7 million indexed cloaked backlinks.
Discourse Forum Software Right to Reply
Note to the Discourse forum software developers etc… feel free to make a comment to explain the link to your home page that’s served from 1.7 million webpages.
I won’t delete your comments as long as they aren’t abusive.
Jeff Atwood Co-Founder of Discourse Forum Response to Hidden Blackhat SEO Links
David Law : Freelance SEO Consultant