Broken link building
Broken link building is finding links on other sites that point to pages which no longer exist, then suggesting your own working page as the replacement. The pitch works because you are reporting a real defect on someone's page, not asking a favor.
Also called: dead link building, 404 link building
Last reviewed
The mechanics: identify a dead URL that several sites still link to, confirm what the original page covered - usually from an archive snapshot - and make sure you have a page that genuinely serves the same purpose. Then tell each linking site the link is broken and mention your page as an option.
Its advantage over most outreach is the reply rate, because the message is useful to the recipient whether or not they take your link. Its limitation is scale: the technique depends on finding clusters of links to a dead resource in your subject area, which is a bounded supply. It works best as a steady background activity rather than a primary strategy.
The most common way it goes wrong is substituting a page that does not actually replace the original. If the dead resource was a detailed statistics page and you offer a product page, the recipient sees a self-interested pitch dressed as a bug report - and the credibility that makes the tactic work is gone.
How Outlink AI runs this in practice: Resource & broken-link.