wallofcerts.link exists solely to serve short, shareable addresses for certificates hosted on Wall of Certificates. It has no account system, no upload feature, and no content of its own beyond redirect/preview pages for links created by Wall of Certificates users.
A link's owner controls whether it expires, and can revoke it at any time — once revoked or expired, the address stops resolving to anything. Addresses are not resold, transferred, or reused once released; a revoked or expired slug simply stops working.
This service is provided "as is," with no guarantee a given link will remain reachable beyond what its owner has configured. See Wall of Certificates' own terms for anything about the certificate content itself.