Backlink: definition, link quality and the metrics to read

A backlink, or inbound link, is a link placed on another website that points to yours. Google reads it as a signal of authority and relevance; generative engines, for their part, retain the sources they cite and the brands they name.

This page helps B2B marketing and SEO managers judge a link before earning it or paying for it: which format, which metrics, which context, which anchor. The overall approach is set out in our guide to netlinking.

What Google does with a backlink

Google treats a link as a recommendation: a publisher associates its page with yours, and that association passes on authority. The signal is rare, since 94–95% of web pages have no backlinks at all (Backlinko, 2026). A link earned on a relevant page therefore already sets a URL apart from most of its competitors.

Before counting links, distinguish four terms:

• Referring domain: the website that links to you, counted only once.
• Source page: the exact URL where the link is placed.
• Target page: your URL that receives the link.
• Anchor text: the clickable text, a semantic clue for both the reader and the search engine.

Google Search Console shows the external links, anchor texts and referring sites of your domain: our guide to Google Search Console shows where to read this report.

Authority passed on and topical relevance

The strength of the source website is not enough to make a link valuable. Google reads four elements together, and what matters is how consistent they are:

• the topic of the source page;
• the sentences surrounding the link;
• the anchor text;
• the topic of the target page.

A link from a modest website aligned with your topic can therefore carry more weight than a link from a prestigious but off-topic one. Raw volume, on the other hand, does not set a target: the page in position 1 has an average of 220 backlinks (Backlinko, 2026), an average that mixes every sector. The useful target is calculated keyword by keyword; our SEO statistics bring together the other benchmarks.

Penguin and link schemes: what Google neutralises

Penguin has been part of Google's core algorithm and has run in real time since 2016: an artificial link is devalued as it is found, without waiting for an update. Google's spam policies target link schemes:

• undeclared paid links, without the sponsored attribute;
• large-scale link exchanges;
• networks of websites built to link (PBN);
• automatically created links.

Link formats and what each one is worth

Not all inbound links originate in the same place. The format already tells you a link's likely value, before you even look at a metric:

For ChatGPT, Perplexity, Gemini or AI Overviews, being named in a cited source counts, whether or not there is a link. Naming is not linking: the mention carries the GEO signal, the link carries the SEO signal, and the two add up.

Recognising an earned link

A credible editorial link answers a simple question: would it improve the source page if Google did not exist? You can recognise it by four signs:

• an explicit reason to cite: a definition, data, a method or an example;
• a passage that tells the reader what they will find after the click;
• a descriptive or brand anchor, never repeated word for word;
• a standalone placement, away from blocks of links added in bulk.

The metrics that qualify a backlink

Each metric answers a different question, and only reading them together qualifies a link or a domain:

Dofollow referring domains: the reference measure

Dozens of links from a single website carry less weight than a few links from different websites: domain diversity reduces dependency and strengthens the signal. The reference measure is therefore the number of unique dofollow referring domains, not the volume of backlinks or an authority score.

A URL's link target is then set against the market. You record the dofollow referring domains of the top ten organic results for its keyword, take the median, then measure the gap with the page you want to strengthen.

A composite score does not replace reading

A composite authority score sums up several signals in a single number. It helps you sort quickly, but Google publishes no such score, and a good score can hide average trust or an irrelevant topic. On marketplaces, it mainly serves as a pricing argument.

Reading the Trust Flow / Citation Flow ratio

Trust Flow and Citation Flow do not necessarily rise together: accumulating links from publishers weaker than you inflates volume and drags trust down. Their ratio sums up the profile of a domain, whether it is yours, a publisher's or a competitor's.

Three profiles depending on the ratio

The Trust Flow / Citation Flow ratio places a domain in one of three profiles:

• 0.80 and above, trusted profile: links come from reliable sources, and volume becomes a genuine target.
• From 0.55 to 0.80, standard profile: trust and volume are balanced, and the topic makes the difference.
• Below 0.55, volume without trust: directories, farms or networks, whose volume you should not try to match.

A competitor with many referring domains but a low ratio therefore does not set your target.

The trust and volume matrix

To judge a specific publisher, reading both metrics together gives four situations, each with its own decision:

Link context: placement, surroundings, consistency

Two links from the same domain, and therefore with the same metrics, can be worth very different amounts. What separates them happens on the page:

• where the link is placed;
• the sentences surrounding it;
• the consistency between source page and target page.

In the body text or in the footer

An in-context link, inserted in a paragraph that already deals with the topic of the target page, offers readable context and a real chance of being clicked. A sitewide link, repeated in the footer or sidebar across an entire website, looks like navigation: rarely clicked and openly SEO-driven, it carries less weight.

Density matters too: the more outbound links a source page contains, the more the value passed to each one is diluted. Once received, authority flows to your business pages through internal linking.

The link's surroundings and topical consistency

Two or three sentences around a link establish its relevance. To check it, remove the link and reread the passage. If it loses a piece of evidence, an example or a definition, the link had a reason to be there. As for the anchor, the best one describes the destination page the way a writer would, without chasing an exact match.

Link assessment checklist

Before accepting or buying a link, five questions help you sort:

• Is the source page indexed, read and maintained?
• Does the paragraph already deal with the topic of the target page?
• Is the link in the body text rather than in the footer?
• Does the source page contain few outbound links?
• Do the website's topics overlap with those of your page?

A page that is nothing more than a catalogue of links fails almost all of them, whatever its metrics.

Anchors: four types, four roles

The anchor tells the reader where the link leads and gives the search engine a clue about the target page. The four anchor types do not have the same role or the same risk:

A credible profile mixes all four types, with brand anchors dominating. The danger comes from repetition: the same exact-match anchor across dozens of domains forms a detectable footprint.

Link attributes: what rel changes

A link without an attribute is followed: rel="dofollow" does not exist, it is the absence of an attribute that makes a link dofollow. Since March 2020, Google has treated nofollow, sponsored and ugc as hints rather than directives; a paid link or one resulting from a partnership is declared with rel="sponsored".

A nofollow link does not count among your dofollow referring domains, but the mention can count for GEO if the domain is cited by AI. The details of the attributes and how to check them are in our article on dofollow links and rel attributes.

The myth of the PR9 backlink

Google's toolbar PageRank was a public score from 0 to 10, calculated page by page, which Google stopped displaying in 2016. Yet the term "PR9" lives on in marketplaces as a selling point for bundles of links, often profile links with no editorial context.

The original logic still holds: a link from a highly recommended page passes on more than a link from a weak page. Its modern equivalent combines a high Trust Flow with topics aligned with your page. A single link of this calibre can be worth more than dozens of weak links for the same budget.

What an authority label does not tell you

When faced with a "PR9" offer or a displayed score, bear in mind that a number tells you nothing about:

• the exact page that will carry the link;
• the consistency of the text around the link;
• the likelihood that the source page is read and indexed;
• the domain's real trust, which only the TF/CF ratio reveals.

Depending on your situation

What comes next depends on the decision you have to make:

• You want to be cited by AI: our article on backlinks and AI details what generative engines retain.
• You are starting with few links: the methods, their effort and their risk are compared in how to get backlinks.
• You are inheriting a link profile: the inventory, anchors and disavow are covered in backlink analysis.
• You need to set targets per page: the per-URL diagnosis and the top-10 median are developed in our backlinks strategy.
• You are considering paying for a link: the sponsored framework and a publisher's eligibility checklist are set out in buying backlinks.

To apply this reading to your domain, the Incremys Offsite media module displays, at the time of writing, the Trust Flow, Citation Flow, Topical Trust Flow and TF/CF profile of your website against your competitors. It sets each URL's target on the median number of dofollow referring domains in the top 10 for its keyword.

FAQ about backlinks

What is a backlink?

A backlink is a link placed on another website that points to a page on yours. Google reads it as a recommendation: it passes on authority and a relevance clue, which is all the stronger when the source page is reliable, read and close to your topic.

Are a backlink and an inbound link the same thing?

Yes, backlink and inbound link mean the same thing: a link from a third-party website to yours. "Backlink" is the most common term, "inbound link" its synonym. Several backlinks from the same website count as only one referring domain.

What is Trust Flow?

Trust Flow is a metric that estimates a domain's trust based on its proximity to websites considered reliable. It is read alongside Citation Flow (link volume) and Topical Trust Flow (the domain's topics). A publisher whose Trust Flow exceeds yours by 5 to 15 points is a very good candidate.

How do you read the Trust Flow / Citation Flow ratio?

The Trust Flow / Citation Flow ratio shows whether a domain's link volume rests on reliable sources. At 0.80 or above, the profile is trusted; between 0.55 and 0.80, it is standard. Below 0.55, it is volume without trust, typical of directories and networks, which you should not try to match.

What is a PR9 backlink?

A PR9 backlink is an outdated selling point: it refers to Google's public PageRank, a score from 0 to 10 that Google has not displayed since 2016. No official tool therefore measures "PR9". The modern equivalent of a very strong link combines a high Trust Flow with topics aligned with your page.

Does a footer link count?

A footer link counts, but it carries much less weight than a link in the body text. Repeated on every page of a website, it looks like navigation, is rarely clicked and brings only one referring domain. Aim instead for a paragraph that already deals with the topic of your page.

Which anchor should you use?

The safest anchor is the brand anchor, which should dominate your profile and also carries the GEO signal. Complement it with partially optimised anchors, which describe the topic in natural language, and a few generic anchors. Keep exact-match anchors for a minority of links, without repeating them word for word.

What is the difference between a backlink and a brand mention?

A backlink is clickable and passes on an SEO signal; a brand mention can exist without a link. For ChatGPT, Perplexity, Gemini or AI Overviews, being named in a cited source counts, with or without a link. Naming is not linking: the mention carries the GEO signal, the link carries the SEO signal, and the two add up.