Lien externe

3 minute read · Updated 28 August 2026

Definition

An external lien points from your website to a page on a different domain. Seen from the receiving site, the same link is a rétrolien — the term describes the direction you are looking from, not a different kind of link.

External links are not a leak to be plugged. Citing sources is normal, useful, and expected. The distinction matters only because external and liens internes serve different purposes and follow different rules.

The economics are opposite

Earning an inbound external link means persuading a stranger: you write something worth citing, you pitch it, you wait, and most of the time nothing happens. You get no say over the texte d'ancrage, the surrounding context, or whether the link survives the next redesign.

An internal link requires none of that. You decide, you write the anchor, it is live. That asymmetry is the whole reason the two are discussed separately — same HTML element, entirely different cost.

Does linking out cost you anything?

In the strict arithmetic, yes: whatever value a page passes on is divided among all of its outgoing links, and an external link takes a share. In practice this is one of the least productive things to optimise. A page with three well-chosen citations and a page with none differ so little that the difference is unmeasurable, while the citations do real work for the reader.

The old habit of adding nofollow to every outbound link to conserve value has not worked since 2009. It discards the share rather than redirecting it.

Where nofollow — or more precisely sponsored et ugc — genuinely belongs is on paid placements and on links you did not choose, such as those in user comments.

Practical handling

Cite where a claim needs a source. A statistic without a link is an assertion.
Do not open every external link in a new tab reflexively. It is a decision about the reader’s context, not a rule.
Check them occasionally. External links rot faster than internal ones, because the other site is under nobody’s control but its own.
Keep automated linking away from them. If you run a tool that turns keywords into links, external destinations should be an explicit choice, never a side effect.

Outbound links and trust

A page that cites nothing asks to be taken on faith. A page that links to the source of every number it uses is checkable, and checkability is most of what separates a reference from an opinion piece.

This matters more than it used to. Where a search engine or an AI assistant is deciding which page to quote, the presence of verifiable sources is part of what makes a page quotable. A statistic with a link behind it can be confirmed; the same statistic bare cannot.

The practical version is unglamorous: link the source you actually used, not a page that mentions it second-hand, and link the specific document rather than the organisation’s homepage.

Keeping them alive

External links rot faster than internal ones, because the destination is under nobody’s control but its own. Domains lapse, sites restructure, articles move behind paywalls. On an archive of any age a steady share of outbound links eventually points at nothing.

A dead outbound link is not a ranking catastrophe, but it is a visible sign that nobody has read the page in years — and on a page that exists to be trusted, that is the damage. A quarterly crawl with any broken-link checker catches them; the fix is either an updated URL or an archived copy.

Where a source has vanished entirely, the honest move is to say so in the sentence rather than quietly deleting the link and leaving the claim standing alone.

Automation and external destinations

Tools that turn keywords into links should point at your own pages by default. An automated rule sending a term to an external destination — an affiliate programme, a partner, a reference site — is a decision with commercial and editorial consequences, and it should be made once per destination, deliberately, not inherited from a keyword list.

Where such rules exist, two safeguards are worth having: a per-page cap so an article never fills with outbound links, and an exclusion for quotations, so a link never appears inside somebody else’s words.

Going deeper: internal links vs. backlinks sets out what each does that the other cannot, and which to do first.

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