I did say that was for people running asterisk and/or ser and added e164.org to the enum search list, which both those applications support...
What gives someone authority in any case? Why should an enum service be left up to governments that want to invade your privacy? or telcos that want to resist and hold onto their market shares for as long as possible?
The concept of enum.164 as conceved by the ITU and IETF is quite good in theory (then again everything is good in theory ), it basically allows someone on non-connected VOIP networks to connect to each other by only knowing their phone number. If applications such as your email were setup to handle mailto records stored in enum you'd only need their normal phone number to send them email. Obviously being able to find someone's complete contact details by way of a simple phone number stored in DNS is quite a scary thing from a privacy point of view.
e164.org isn't run by a company looking to spam you every way possible, it isn't run by a government body looking to more easily spy on you. It is run by a couple of friends for the purpose of dynamic point to point phone calls without a single point of failure (currently 9 DNS servers round the world distributing load), the users dictate how little or how much information people are comfortable storing with the service.
Jeff Pulver in one of his blog postings suggested multiple enum zones would benefit the community. In fact he went further then that and is trying to push for .tel TLD for this specific purpose.
So at the end of the day authoritative is a fairly scary term, especially if you happen to live under a dictatorship and governments force their citizens to supply them information to be stored in "authorative" DNS zones.
There is a lot of documented information out there both pro and anti (mostly due to vested interests in having it or not having it) with the "authoritive" enum.164 zone. For more information on e164.org you can go here for a general intro as to how it works.