Links are a fundamental part of SEO and the World Wide Web as a whole.
Since the web’s original inception links have been key. Interlinked information was one of Tim Berners-Lee’s fundamental concepts when he developed HTML and HTTP. Although Tim’s vision was more along the lines of citations in scientific papers linking to other scientific papers, the concept of interlinked information underpins the World Wide Web, SEO, and ranking positions in search engine results.
While backlinks do influence page rankings, the amount of influence varies between backlinks. It’s not quite as simple as more backlinks equals better SEO, and I’m going to try and explain this in this blog post.
What is a backlink?
A backlink is a link from one website to another. A backlink is made up of:
- A backlink is a link from one website to another. A backlink is made up of:
- The target URL (the page or resource the link leads to)
- The target attribute (which tells the browser how to behave when the link is clicked)
- The rel attribute (which defines the relationship between pages being linked to and from)
- Anchor text (the link text you’d click on to follow the link)
Why backlinks matter for SEO.
In simple terms, backlinks are a bit like an endorsement of your website, by another website.
Just like real world endorsements, how seriously these endorsements are taken cary according to their source.
For example, if I happened to mention to my boss that I had an ingrowing toenail, and he offered to “sort it out because he does his wife’s toenails” that’s not going to be quite as solution orientated for me as a chiropodist with letters after their name offering to sort it out “because they went to university about it, and now get paid to do that”.
It’s a similar situation with backlinks.
If your website is listed on yell.com you get a backlink, which is good, right? Then again, anyone can list on yell.com, so who’s better? Is it the bricklayer with JUST the yell.com backlink or is it the bricklayer listed on yell.com and the Association of Brickwork Contractors members directory?
Which of these two bricklayers do you think ranks better in search engine results?
At this point, you might be tempted to think “I’ll go and get a gazillion backlinks!” But please don’t do that. Here’s why.
Why you need to be a bit careful with backlinks.
Google’s product is serving relevant results. Google being good at this is what sets them apart from other search engines. This is why more people use Google, and because of that, companies want their sites to be on page one of Google.
The want of companies to get to page one of Google can tempt them into using their website (and it’s backlinks) to manipulate Google’s algorithm to gain improved rankings. Should the companies doing this succeed, there’s a chance they could invalidate Google’s product (serving relevant results) and then less people would use Google.
Obviously Google don’t want their product to be invalidated, so they have quite a lot of anti-manipulation measures in place. If your website is deemed to be manipulating Google’s algorithm, they could simply de-rank your website and it wouldn’t be found in Google search result.
So if you go and buy a gazillion backlinks and Google detect this, it’s going to look like you’re manipulating them, and they’ll penalise you for this, so that you don’t invalidate their product.
So if you’re going to use backlinks to improve your website’s rankings, you can’t achieve this by buying lots of backlinks. At best this won’t do anything, at worst you’ll be penalised for manipulating the algorithm.
Your sites backlink profile, if done in a legitimate Manner, will grow slowly and steadily over time. This involves ongoing time, and a consistent effort.
Why some backlinks don’t have any effect.
There are people that sell backlinks. Where they get these backlinks can be quite varied and some sources can be completely irrelevant.
If there’s a blog post with comments open, and someone links to your website in one of these comments, that is technically a backlink… but it’s probably ignored by Google. If you paid for that backlink, you did get a backlink. Unfortunately, because it’s been ignored by google (as it’s just a comment on a blog post), it doesn’t have any effect.
The reason it’s ignored is because anyone could do that, and it’s not really an endorsement by the owner of the blog.
The situation is fairly similar for business directories, forums, link farms and so on.
As you’re probably getting the picture by now, not all backlinks have the same effect.
There has to be some means of “the backlink from the Association of Brickwork Contractors has a more positive effect on your site compared to the backlink in a comment on a blog post about bricks”.
How is that done?
Google Pagerank.
Google page rank is used to rank pages (although there are other additional ranking factors) in search engine results. The page rank formula is based on sites linking to each other.
Pagerank calculates authority, which is quite a heavily weighted ranking factor.
Authority is calculated based on backlinks. How much authority is passed on from one site to the other varies according to the amount of incoming links, outgoing links and authority each linking site has.
Pagerank isn’t the easiest of things to understand.
This video provides an excellent easy to understand explanation of pagerank. I’d highly recommend that you watch this to gain an understanding of pagerank.
This video introduces a fairly key concept which is link equity (otherwise known as link juice) which determines how much authority of a site being linked from is passed on to the site being linked to.
How much link equity passed on from one site to another varies according to how many outlinks a site has.
If you get a backlink from a high authority site, you’ll only get a good amount of authority passed to your site if the backlinking site doesn’t link to too many other sites.
While it might feel like an achievement to get a backlink from nytimes.com with it’s domain authority of 100, nytimes.com backlinks to 434,000 other sites, so you only gain a small proportion of link equity (imagine 100/434000 = 0.00023).
If nytimes.com liked to your site and one other your site would receive a lot more link equity (imagine 100/2 = 50 that’s a lot more than 0.00023).
It’s not quite as linear as the sums mentioned here, and also pagerank is a hidden value, domain authority is a “guess at pagerank” that was made up by Moz when Google hid pagerank values, which they had to do to stop people gaming the algorithm and potentially invalidating their product.
Wait. What? Domain authority is a guess?
SEO tools, domain authority and domain rank.
As you’re most likely getting the picture by now, Google keeps quite a lot of stuff secret. They pretty much have to do this to stop the marketing people gaming their algorithm to make an irrelevant website rank.
Although page rank isn’t publicised, SEO tools provide metrics such as domain authority (Moz, Semrush) and Domain rank (AHrefs). These are arbitrary metrics derived from a mixture of what these tools have crawled, combined with the pagerank algorithm.
What these tools are providing is effectively a next best guess at pagerank scores. How accurate these tools, and DA/DR are, is a bit questionable simply because Google don’t explicitly state how their operating and there’s some variation with regard to what had and hasn’t been crawled by these tools, which is likely to differ from what google has crawled.
I mean… what else are they going to do? It’s not like Google are going to tell them.
Quick recap.
- Backlinks heavily influence rankings.
- How rankings are worked out is based (partially) on the pagerank algorithm.
- Google has a lot of anti manipulation in place.
- Attempts to manipulate Google’s algorithm can lead to penalisation of deranking.
- You can’t do things like madd backlinking without a risk of penalisation.
- Legitimate backlink outreach results in a a backlink profile growing slowly and steadily overt time.
- The pagerank algorithm operates (partially) on inlinks and outlinks to work out how much authority (or link equity/link juice) is passed on from one site to another.
- Due to pagerank, not all backlinks are equal with regard to how much authority they pass on.
- The true domain authority of websites isn’t publicly available information.
- SEO tools make a best guess at authority based on pagerank, and what they’ve crawled, but this isn’t the same as Google’s data set so it’s a next best guess.
Really what all the above translates to, is that you’re going to gain more benefit from procuring a few high quality backlinks over time than you are from any kind of mass backlinking or scatter gun approach… but how do you do that?
Backlink relative value tool!
This tool isn’t a replacement for pagerank. This tool doesn’t predict rankings. This tool involves you getting stats out of your SEO tools and using them to compare domains. The domain comparison should give you an indication of where to focus your backlink efforts.
The objective is this tool is to:
- Compare relative backlink value potential
- Demonstrate link equity dilution
- Help you make smarter outreach/link choices
This tool is really orientated to comparing domains to allow you to gain an idea of where it’s worth focussing your efforts.
The formula this tool uses is very simple:
Where:
- DA/DR is a proxy for page authority (analogous to PageRank PR(Ti))
- Outlinks represents link dilution (like C(Ti)PR(Ti))
- Follow weight reduces the score if the link is nofollow
- follow: x 1
- nofollow: x 0.25
- Relevance is an optional topical multiplier:
- high: x 1.2
- medium: x 1.0
- low: x 0.7
The orginal pagerank formula is:
Where:
- PR(A) = PageRank of page A
- PR(Ti) = PageRank of page Ti linking to A
- C(Ti) = number of outbound links on Ti (dilution)
- d = damping factor (usually 0.85)
- k = number of pages linking to A
The tool below mirrors the core concept of pagerank:
Key Differences from True PageRank
No iterative graph calculation
True PageRank iterates until convergence:
The tool computes a single-page loosely defined simple equivalent:
I’m sure you can see the difference.
DA/DR is a “kind of like” guesstimate, not true PageRank
But DA/DR are the best we’ve got as far as a value from which a subsequent value can be derived.
No damping factor
Pagerank uses a random “jump”:
The tool below ignores this, which is acceptable for comparing a small set of pages.
Single-page view
PageRank distributes rank across all linking pages:
The formula of the tool below treats pages individually.
Tool Summary:
The tool is calculating a backlink effectiveness score:
Then using this score to compare domains.
So this tool:
- Captures the principle of link dilution
- Shows relative authority contribution
- Is PageRank-inspired, but not actual PageRank
Using this comparison tool.
You’ll need to use an SEO tool such as AHrefs or Semrush to get the DA and outlink values.
When you find some appealing looking backlink sources, use the data in your SEO tool to populate the table.
Click compare and you’ll see the domains sorted from best to worst in value.
Relative backlink evaluator
Simple comparison: Score = DA/DR ÷ Outlinks, adjusted by Follow/Nofollow and Relevance.
Frequently Asked Questions about Backlinks.
What is a backlink?
A backlink is a hyperlink from another website to your own web page. It is often considered a “vote of confidence” and can influence search engine rankings.
Why are backlinks important for SEO?
Backlinks help search engines determine the authority, relevance, and trustworthiness of your site. Pages with high-quality backlinks often rank higher in search results.
Do all backlinks carry the same value?
No. The value of a backlink depends on factors such as the authority of the linking site, topical relevance, number of outbound links, and whether the link is follow or nofollow.
What is the difference between follow and nofollow links?
ollow links pass SEO value (link equity) to your page, whereas nofollow links do not pass full SEO value but can still generate referral traffic and provide partial influence.
How can I get high-quality backlinks?
Focus on creating valuable, relevant content that others want to reference. Guest posting, press releases, and partnerships with authoritative sites are common strategies.
