Estimated Read Time: 5 Minutes
What Is a Backlink?
A link is an online reference to content you can access with the click of a mouse. A link will take you to another spot within a page or to an entirely different page or website altogether.
A backlink is an incoming link from an external source – a website other than your own.
An SEO (search engine optimization) backlink is no different; the “SEO” in front merely references the fact that links influence your search engine rankings. That influence can be good or bad, positive, negative, or neutral depending on factors discussed below.
Why Are Backlinks Important?
Backlinks are important because they are ranking signals for Google. They are not the only considerations Google uses to decide who ranks where but they are among the top 4 most important according to SEO Industry studies.
Google treats backlinks like “votes” or endorsements for your content. It assumes website owners link to content they find valuable – content that helps them (or their audience) do what they need to do. All things being equal, the more “votes” or backlinks your content earns and acquires, the higher it will rank.
This post explains SEO backlinks, the concepts of SEO equity, link equity, and link juice, and how different link sources and attributes can help or hurt your rankings.
SEO Equity, Link Equity, and Link Juice
Think of the Internet as one gigantic system of interconnected web pages. As content ages and more and more people discover, link to, and share it, it earns and acquires more and more authority and backlinks.
The combined value of authority and backlinks adds up to your website’s overall ranking potential – its ability to rank well in search results. SEOs tend to refer to this SEO equity.
Link equity or link juice, on the other hand, is a reference to the amount of SEO equity that gets transferred from source to destination when you link two pages together. Link equity is a subset of your overall SEO equity.
SEO equity, link equity and link juice are all terms made up by SEOs who theorize how Google works. They are not Google terms. If you search Google’s Webmaster Academy, you will not find references to SEO equity, link equity, or link juice anywhere. They are the language of SEOs not Google.
How Link Equity Flows
The illustration below shows how link equity is believed to flow across the Internet.
Website D’s Home page (in the middle of the diagram) has an accumulated SEO equity of 120 “points”. 100 of those points come from a single backlink on an authoritative website, Website A.
Websites B and C each also contribute 10 points each to D’s overall SEO equity. Their sites are less reputable so their links pass less juice.
Link equity flows within a website as well as across different domains. In this same example, you can see that Website D’s SEO equity gets distributed to internal pages linked to from its Home page. The About, Services, Blog, and Contact pages each receive one-quarter of the Home page’s total SEO equity or 30 points a page.
Not All Links Have Equal Value
So why is it that website A can pass 100 points whereas websites B and C only pass 10? It has to do with trust, reputation, and authority.
An authoritative website is a very high-quality website that has earned the trust and respect of its peers and searching audience. Authority websites tend to publish large quantities of comprehensive, detailed, accurate, and verifiable information and then link out to other websites that do the same. Visitors trust the content on authoritative websites and willingly advocate on their behalf by freely linking to them and sharing them with others.
Examples of authoritative websites include common, everyday names like Apple, Amazon, Harvard University, Facebook, Forbes, Microsoft, NASA, The Mayo Clinic, Wikipedia, and Youtube. These are all trusted websites that have been around a long time and earned millions, if not billions, of backlinks.
A backlink from an authoritative website passes more link juice just because it has accumulated more than the norm. Poor quality websites pass little link juice, and the juice they do pass might actually be harmful if the site participates in schemes Google devalues or penalizes.
More on that in a minute.
What qualifies as a low-quality link?
Google publishes quality guidelines that define “link schemes” as links intended to manipulate a site’s ranking in Google search results. Examples include:
- buying and selling backlinks;
- excessive link exchanges or partner pages exclusively for the sake of cross-linking;
- large-scale article marketing or guest posting campaigns with keyword-rich anchor text links; and
- using automated programs or services to create links to your site.
Google also considers links that were not editorially placed as bad. Common examples of non-editorially placed links include widely distributed site-wide footer and template links, links from poor quality directory sites (that accept anything), affiliate links (where you are compensated for an endorsement), and non-helpful blog and forum comments placed just as a way to stuff a backlink onto someone else’s site.
These types of links can result in a site-wide or page penalty, a warning, and/or the loss of rankings.
Website owners can control the flow of link juice using link attributes. Link attributes include things like the link title, destination, and anchor text (the clickable words that appear on the page).
The nofollow link attribute prevents link juice from flowing to the destination page. The juice is not redistributed to other links on the page. It is simply dropped.
This is an example of a Contact Us page link that includes the nofollow attribute.
- <a> paired with </a> specifies the start and end of the link.
- href is the first attribute. It indicates the link destination.
- rel=”nofollow” tells search engines you do not want to pass SEO equity to the link destination.
- The word or words appearing after that and between close bracket (>) and the end of the link (</a>) are the words you want to be clickable.
Google recommends using the nofollow tag in instances where you might be encroaching upon their guidelines. Most blog and forum owners also use nofollow links in their comment moderation systems to deters visitors from leaving useless remarks paired with a self-serving backlink (like shown above).
There are a lot of instances where Google Guidelines are not clear. Nofollow links give you an option for dealing with them and possibly avoiding a future problem.
If you have questions or interesting observations about backlinks, please share them below.