Broken Link is a link that points to a missing, moved, blocked, or otherwise unavailable destination.
It matters because technical issues can prevent great content from being discovered, rendered, indexed, or trusted. Strong technical foundations protect rankings during redesigns, migrations, content expansion, and platform changes.
Example
An article’s link to a guide returns 404 because the guide moved. Update the link to the verified relevant destination and test that normal public URL; choosing an unrelated live page would remove the error without helping the reader.