Looks a lot like the resource names on AWS [1]
<!-- AWS Elastic Beanstalk application version --> arn:aws:elasticbeanstalk:us-east-1:123456789012:environment/My App/MyEnvironment
<!-- IAM user name --> arn:aws:iam::123456789012:user/David
<!-- Amazon RDS tag --> arn:aws:rds:eu-west-1:001234567890:db:mysql-db
<!-- Amazon S3 bucket (and all objects in it)--> arn:aws:s3:::my_corporate_bucket/*
http://docs.aws.amazon.com/general/latest/gr/aws-arns-and-na...
It should. There's a reason for that. :)
What's the reason, and why didn't they just use URNs?
The reason is because they're based off the same principle. "ARN" stands for "Amazon Resource Name".
I don't know why they didn't use URNs. Probably because nobody else does.
I think the implication is meant to be "they look like URNs because they are".
Except that they're not; rather, they're ARNs. URNs must begun with 'urn:'. It doesn't make a lot of sense that they're not URNs, but…they're not.
It's a universal namespace, just like UUIDs, but with just enough extra sauce to make it theoretically possible to do interesting things with it. So 'urn:isbn:0451450523' might represent The Last Unicorn, and if you fed it to your Kindle it might enable you to buy it, and if you fed it into Nook ditto, and if you fed it into Project Gutenberg you might get a notice that it won't fall out of copyright until A.D. 3172, and if you fed it into your browser it might do any of those things or just look it up on ibiblio or Wikipedia.
Unfortunately, like many good ideas, it didn't take off because folks couldn't imagine a profitable use for it.