> Why are URNs not more popular? […] Why has it not catched on? 1. Usability: a developer must register a URN with IANA which is a huge hurdle compared with mi

> Why are URNs not more popular? […] Why has it not catched on? 1. Usability: a developer must register a URN with IANA which is a huge hurdle compared with minting a URI which only requires control over an email address or domain name. <http://enwp.org/Tag_URI_scheme http://enwp.org/Tag_URI_scheme> 2. Cumulative advantage: everyone knows how to dereference an IRI/URI/URL with the HTTP scheme because the software capable of doing so is deployed million-fold, and dereferencing may also lead to a representation describing the resource which is readable by humans and machines. One can't really do the same with URNs, or at the very least it's much less convenient. 3. Flexibility: if you mint a PURL <http://enwp.org/PURL http://enwp.org/PURL> with an extremely long lived redirecting service (e.g. <http://w3id.org http://w3id.org> or <http://purl.org http://purl.org>), you are able to point the identifier to different resources, this indirection leaves you with options over the time of its existence. URNs have no redirects, they need to be perfect from the start, which is not a reasonable assumption when humans are involved.