The namespaces protocol's pilot namespace is a Twitter namespace for which the rental parameters include an indefinite time-based expiration and a manual revoke authority set to the namespace itself. It also uses the "claim approver" feature of the namespace to require prior approval before renting.
Any user can prove ownership of their twitter handle by tweeting their public key. Once verified, they can rent the NFT indefinitely from the namespace. Successfully claiming the NFT also automatically sets a forward and reverse resolution entry in the namespace so that its current owner can be quickly determined. This allows for easy lookups to resolve an address from a twitter handle and vice-versa.