What is a Backlink? Understanding Inbound Links in SEO

A backlink — or inbound link — is a hyperlink placed on website A that points to website B. When a major publication writes an article and cites your study with a link to your page, your site receives a backlink from that publication. Simple in definition, but fundamental in its impact on organic search.

Backlinks are one of the three pillars of SEO — alongside content and technical optimisation — and one of the hardest signals to manipulate artificially over the long term. That's precisely what makes them one of Google's most reliable signals.

Why Does Google Care About Backlinks?

The idea was born with Larry Page and Sergey Brin in 1998, Google's founders. They had the intuition that the web resembles an academic citation system: if a paper is frequently cited by others, it's probably important. They transposed this principle to the web: a page frequently linked by other pages is probably more useful.

This is the foundation of PageRank — Google's first algorithm, named after Larry Page himself. Since then, the algorithm has been enriched with hundreds of signals, but backlinks remain one of the most powerful.

Why? Because they represent a human decision. When someone adds a link to your page, they're implicitly saying "this page is worth reading." That decision cannot easily be faked at scale without Google detecting it.

Not All Backlinks Are Equal

The first thing to understand about backlinks: quality trumps quantity. A single link from Wikipedia or a major national publication can outweigh hundreds of links from low-audience, low-authority sites.

Factors that influence the value of a backlink:

Domain Authority

The more powerful the linking site itself — measured by the number and quality of its own backlinks — the higher the transferred value ("link juice"). SEO tools like Semrush, Ahrefs, or Moz assign a Domain Authority (DA) score from 0 to 100.

Topical Relevance

A link from a site covering the same subject as yours is considered more relevant. A gardening blog linking to your seed shop carries more semantic value than a generic directory link.

Anchor Text

The anchor is the clickable text of the link. "Click here" provides no semantic information. "SEO consultant in Brive-la-Gaillarde" clearly signals to Google what the destination page is about. A natural mix of varied anchors (brand name, target keyword, URL, generic anchors) is what Google looks for.

The rel Attribute (follow vs nofollow)

By default, a link passes PageRank. But there are special attributes:

• rel="nofollow": doesn't pass PageRank (often used in comments, paid press)
• rel="sponsored": for paid links (partnerships, advertising)
• rel="ugc": for user-generated content

Nofollow links have less direct value, but aren't without interest — they can generate traffic and contribute to a natural backlink profile.

Position on the Page

A link in the main body of an article carries more value than one in the footer or a sidebar loaded with links. The implicit editoriality of a link inserted in text signals greater confidence.

How to Earn Quality Backlinks?

This is SEO's million-dollar question. There's no lasting shortcut, but several strategies work.

Content Worth Citing

The best long-term link building strategy is creating content so useful and original that others naturally want to cite it. This is called link bait (link-attracting content):

• Original studies and data (surveys, sector analyses)
• Exhaustive reference guides on a niche topic
• Free tools (calculators, templates)
• Well-designed infographics with visual data

Digital PR and Press Relations

Approach journalists and bloggers covering your sector. Offer them contributions, interviews, exclusive data. Natural press coverage generates high-quality backlinks.

Unlinked Mentions (Link Reclamation)

Sometimes someone mentions your brand or product without linking. Use Google Alerts or Mention to detect these mentions, then contact the editor to suggest adding the link.

Editorial Partnerships

Cross-collaborations with complementary sites: guest posts, cross-interviews, co-publications. The important thing is that the content has value independently of the link.

Directories and Resource Lists

Some sector directories or resource lists have a real audience and genuine authority. Getting listed in these can generate both traffic and a useful link.

What to Absolutely Avoid

Google has become very effective at detecting artificial links. The following practices can trigger severe penalties:

• Buying links in bulk from networks of sites created for this purpose (PBN — Private Blog Networks)
• Excessive reciprocal link exchanges ("you link me, I'll link you")
• Using software that automatically creates links in comments, forums, profiles
• Placing links in footers or widgets distributed en masse

Since the Penguin update (2012) and its successive iterations, these tactics are actively monitored. And since 2022, Google confirmed the link disavow tool remains available — proof that penalties for toxic links are very real.

Evaluating and Monitoring Your Backlink Profile

Having backlinks is good. Knowing what you have is essential.

Main tools for analysing your link profile:

• Google Search Console → "Links" tab: free, direct Google data
• Ahrefs: the most comprehensive, but paid
• Semrush: very comprehensive, with a link toxicity audit
• Majestic: specialised in link analysis (Trust Flow / Citation Flow metrics)

What to monitor regularly:

• Total number of referring domains (not just links — one site can point multiple times)
• Trend over time (natural growth = good sign)
• Most frequent anchors (too many links with the same exact anchor = suspicious signal)
• Links from low-authority or unrelated-topic domains

Internal Links: the Neglected Side of Link Building

Backlinks come from other sites. But internal links — those you create yourself between your own pages — also play a role in distributing authority within your site.

An article well-linked from your homepage, category pages, and other articles receives more internal authority than an orphan page. That's why good site architecture and an internal linking strategy are integral parts of SEO.

Moving to Practice

Understanding backlinks theoretically is useful. Living them in context creates genuine understanding. Our SEO simulator has you making link-building decisions in realistic scenarios — is it worth accepting this editorial partnership, or better to invest in content?

If you want to evaluate your current link profile and identify opportunities in your sector, an SEO audit always includes a backlink analysis. To deepen the fundamentals, check out our complete guide to learning SEO.

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Article written by Alexandre De Sousa, SEO & GEO consultant, founder of iZZi. Last updated: May 2026.