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We analyzed 1 million backlinks via 10 random sample sets of 100,000 backlinks across 10 different websites from a variety of business verticals to determine how the link metrics from those backlinks would impact gains or losses in organic search visibility.
A Quick Word About Link Analysis at Scale
The goal is not to manually review each individual referring URL one by one. That would suck! I don’t know any SEOs who wake up in the morning and look forward to doing a task of such absurdity.
However, a more realistic goal is to look for patterns, trends and commonalities among link metrics for a given URL to determine whether or not it’s an unnatural link.
P.S. – Powerful crawlers and anchor text classifiers like URL profiler can literally save you hundreds of hours of grunt work. We’re in no way, shape or form affiliated with them, but we highly recommend checking them out!
Upon completing a link audit, you should have a few outputs to work with:
- Danger List – These are the links that are extremely likely to be unnatural and should be considered for disavowal.
- Caution List – These are the links that could be unnatural and must be manually audited to determine if they are safe or dangerous.
- Safe List – These are trustworthy, authoritative links that are most likely to be natural. Getting more of these will help boost organic visibility.
- Link Schemes – These are large groups of similar links that are coming from the same source and are the most probable cause of site-wide links.
- Link Opportunities – Some websites (especially popular brands) earn natural, high-quality links without knowing it. An audit will help you discover those sources so you can build relationships and earn more links.
- Link Equity Consolidation – In almost every case, there are authoritative inbound links pointing to 404 pages on any given website. Those 404 pages should be revived by implementing 301 redirects to a live final destination URL to reclaim the lost link equity.
Link Metrics Considered
The link metrics can be segmented into 4 key categories:
These are the primary link metrics that will be used to evaluate Udemy’s backlink profile:
Majestic Citation Flow – Rates how influential a URL may be based on how many sites are linking to it, and based on a 100-point scale.
Majestic Trust Flow – Predicts how trustworthy a page is based on the trustworthiness of those sites that are linking to it, based on a 100-point scale.
Moz Spam Score – Rates the level of penalization risk associated with a given URL, based on a scale of 0 – 17 where any rating of 11 or higher is likely to be spam.
Moz Domain Authority – An overall website rating that is calculated by metrics, such as linking domains, number of total links, MozRank, MozTrust, into a single 100-point logarithmic score.
Ahrefs Referring IP C-Class Diversity – IP Addresses are divided into lettered blocks (AAA.BBB.CCC.DDD). The more referring C-Class Duplicates that exist within the link profile indicates that the site is likely to be engaging in link networking.
Ahrefs URL Rating – Prediction score for how well a page is likely to rank in organic search results, based on a 0-100 scale.
We included the following 10 websites in our study:
Analysis of 1 Million Backlinks: Udemy
Udemy is an online learning and teaching marketplace with over 42,000 courses and 14 million students. With Udemy, you can learn programming, marketing, data science and more – all at your own pace and schedule.
Key Insights: Udemy’s Link Profile
- Referring Domain Velocity: Udemy has built links from more referring domains over time than key competitors. On average, they earn links from approximately 2,000 referring domains per month. That level of referring domain growth has been instrumental to their organic search visibility.
- Sitewide Linking: The most unnatural link type detected on Udemy’s link profile was sitewide links. A sizeable portion of those links were widget links. A referring domain to backlink ratio of approximately 94:1 is a cause for concern.
Ahrefs reveals that EFLClassroom is linking to Udemy over 400k times:
Google calls out that the site is likely hacked and the meta description clearly states that it's a directory link website. This is a strong indicator of low-quality links:
Clear sign of an untrustworthy website that lacks brand credibility. Not the type of website you want 400,000 backlinks from.
After data sterilization, approximately 48,000 live links were found:
The distribution is showing that most referring domains have an authority of 30 or less, however there are a few outliers at DA 30 and DA 90:
Outlier at DA 30 – Newmarksdoor.com. This is your typical DA 30 blog. Upon reviewing the site, it looks pretty safe. But let’s see where all those links are coming from.
Well I’ll be darned. It’s a sidebar widget link embedded into the template of every page on the site. This is the type of link that could potentially get you into trouble, especially given that Google recently issued a warning on sitewide widget links.
This could be perceived as unnatural linking at some point, so I’d recommend that Udemy ask them to implement a rel=nofollow attribute to remain on the safe side.
Normally this may not be worth Udemy’s time, but because there are so many incoming widget links, it would behoove them to nip this potential problem in the bud. The referring URL level distribution tells us that most links are of low authority; however, there appears to be an outlier at URL Rating 7:
This site that is loaded with strange links was the source of the URL Rating 7 outlier:
The normalized distribution proves that most referring domains have a Trust Flow rating of zero. The drop-off after zero is pretty significant, which means that the majority of referring domains are not trustworthy:
The URL Citation Flow is showing a drop-off that is slightly less intense than the Domain Trust Flow. We can still conclude that the vast majority of these referring links are not influential, and very few of them are positively impacting Udemy:
Example of a link from an untrustworthy source:
Moz’s Spam Score (0-17 scale) recommends reviewing links with a score above 10:
Here’s a good example of classic link spam – just a list of links from a foreign TLD:
Upon reviewing Moz’s Spam report, I noticed a huge number of .org links with a score of 11. Those links are collegiate rip-off sites, posing as affiliates and trying to steal leads:
The site’s footer tells us everything we need to know:
The Duplicate IP C-Class is a staggering 96%, which is a cause for further investigation:
An example of low-quality links from different referring domains all hosted on the same IP C-Class. This is commonly known as a “link network”:
These are the most commonly used phrases that external sites use when linking to Udemy:
Most of Udemy’s backlinks are coming from content and blog posts:
Udemy has acquired authority, relevance and trust over time – largely by building a product that is useful, practical and makes people’s lives easier:
The #1 issue affecting Udemy’s link profile is referring root domain diversity. Our sample shows 3.9k domains to 100,000 links:
Our sample was able to identify a small batch of safe links and danger links, but approximately ¾ of the link samples could not be determined programmatically. It is recommended that these links be reviewed manually to determine their fate:
Due to the nature of Udemy’s business model, their content earns lots of links naturally. Udemy’s content library consists of a broad set of topics, which allows them to earn links from many different relevant sources like:
- Huffington Post
- Business Insider
- Tech Crunch
- The Next Web
Example of a high-quality link from Mashable:
Collaborations have also been a golden source of link wealth for Udemy:
We can see that specific pages that are dedicated to specific courses can become popular among niche audiences and earn lots of targeted backlinks:
Partner with Emerging Influencers
Continuing to partner with emerging influencers in niche topics will bring their audience to Udemy.
Learn More: Influencer Marketing 101: How to Succeed
This is an example of a link from Guitarworld.com that was built to Udemy by a popular guitar teacher. Gaining the trust of these niche audiences are key to winning the SEO battle (as well as customer growth, retention, and revenue battle!):
Disavow Rip-Off Collegiate .ORG Domains
These are the most unnatural links to Udemy because they are duplicate sites from the same IP C-Class that are intended to manipulate page-rank as well as web visitors.
There is no difference between the .com and.org domain:
Content Opportunity: Udemy Success Center
There’s nothing people love more than an a good old-fashioned success story, so why not give it to them? I bet that if Udemy interviewed prospective customers, one of the friction points would be the uncertainty of “What happens next?”
A new landing page focusing on customer success stories would be a great way to generate some P.R. buzz while building positive sentiment around the brand.
Testimonial style videos could be a cool option to explore as well.
Upon searching for customer success stories, I only found one poorly executed blog post from 2013:
Learn More: The Ultimate Guide to Link Building with Content
Build Diverse, Non-Branded Anchor Text Links
While Udemy’s anchor text mostly follows a natural pattern with 61% branded anchors, 34% miscellaneous anchor text is quite high. Ideally, there would be less disparity among miscellaneous versus commercial anchors, with commercial being closer to 30% rather than where it currently sits at 5%.
Reclaim Link Equity & Fix Broken Backlink Targets
Approximately 34k links are pointing to 8k broken targets on Udemy.com:
Udemy is a great brand and has done a great job standing out in a very competitive marketplace.
They’re at a low risk for link penalization, which is great! But that doesn’t mean they should ignore some of the warning signs identified in this mini audit.
Implementing the recommended actions will help them improve their organic search visibility and get even further ahead of the competition.
Any SEO-savvy marketer with technical chops can likely implement these recommendations. If you’re a marketer looking to improve your link game, check out our ultimate guide to link building.
If you're not an SEO-savvy marketer or you just don't have the time, Single Grain can help you! We’ve helped business of all sizes improve their marketing ROI, ultimately increasing revenue – check out some of our case studies here.
Click the green button for your FREE consultation to see how we can help you. (Just wanna geek out about SEO? That’s cool, too! Let's chat.)
Have you done any link audits lately? What’s your process like? Let us know in the comments below!