How do I love thee communications? Let me ENUM the ways

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Last week, Ars Technica had a great in-depth article on ENUM. For those who do not know, ENUM is a standardized method to use Internet technologies to translate your old, staid, telephone number (e.g. +12125551212 or +442076555555) into an Internet device connection. That connection could be simple voice, such as allowing you to use a VoIP connection rather than going through the PSTN (public switched telephone network) that we all love/hate, or even identifying a Skype user ID or email address based on the telephone number.

ENUM really has two purposes, which are related but are not exactly the same. The first is evolutionary, the second more radical.

  1. Free from the carriers: If you enter a telephone number, you are essentially telling your phone company or carrier, "go to this country, this area code, lookup this number, find out which carrier holds the number, then connect to them and through them to a particular phone." You are connecting through carriers, the same way you always have done. But now, you have VoIP phones. You are no longer directly bound to a traditional carrier; you may not even be bound to a carrier at all. There are well-defined ways of publishing your VoIP phone contact info over the Internet. ENUM allows you to publish a number and say, "hey, connect to me through the Internet at this VoIP address, which is how you would get to me." You are setting yourself free from the carriers (at least to some extent). In the (almost) words of Sting, "if you love some(ph)one, set them free." This is evolutionary, it assumes phones are pretty much the same as they always were and serve the same purpose, but we want to have a better, freer, cheaper route to get to them.
  2. Universal identifier: Somewhere down the line, Internet people began to realize that we have a lot of identifiers. We have one or more email addresses, Skype IDs, Gmail IDs, Yahoo IDs, the list goes on and on. Wouldn't it be great to have a single identifier that is me but can access all of the other parts? In essence, we are looking for something like a really smart email list. Just like I can set up an email list and have it send the email to 5 different email addresses, I want a single identifier that will allow anyone to reach me, and is smart enough to say, "I am trying to reach you via email, tell me which way to go," or "I am trying via Skype, which way?" Since everyone has a phone number, the theory goes, why not use the phone number as that unique identifier, and have a system, let's call it something really catchy, say, "ENUM," to translate from the person's unique identifier to the various methods of reaching them.

The first method is slowly gaining some ground, but not very much., probably the largest and most well-known Public ENUM provider, says it has just under 47MM allocations. Considering that the total possible numbers under current numbering schemes is just under 100BN, and the US alone is estimated to have close to 300MM phone lines, these numbers really are tiny. does not publish how many are actually in use. There are two great challenges to adoption, one from the user side, one from the carrier side. From the user side, it is useful for dialing in, terrible for dialing out. Let's explain why. If I am calling you, I don't need to publish my ENUM, I just need yours. In having yours, I can get a much cheaper route to you. But you gain nothing from it. Similarly, when you try to call me, it is really useful to you if I have published my ENUM, but I gain nothing; you are the one who saves on all the carrier interchange fees. The net result is that the only real incentive to publish ENUM is, well, none. Who is left? The carriers. The carriers, who probably provided you with a telephone number, like these interchange fees. Sure, it would be nice if someone contacted them directly, but in the interim, everyone is getting a small piece of the pie, with the whole pie provided by the call originator. All in all, not a great recipe for them to publish ENUM either. Finally, as pointed out in the Ars Technica article, ENUM explicitly puts control of the number in the hands of the end-user, i.e. the phone subscriber. Needless to say, the carriers are not exactly going to be thrilled about relinquishing control.

From a universal identifier perspective, I do not believe ENUM will take off, due to sheer usability and control issues. From the control perspective, most numbers are still controlled by carriers. Unless and until it becomes easily possible for someone to purchase (not lease, rent or otherwise) a telephone number and directly control it, carriers will be the gateway for telephone numbers, which means users will not view them as their own. Yes, you can buy low-cost DIDs from many forwarding and ITSPs, but these are still owned by them and they remain the gateways. As long as this holds true, people will not view them as their unique identifier, but rather tied to whatever phone line they have, not to themselves. Additionally, in many countries and especially the United States, people do not want to be globally identified by a number, with apologies (but not too many) to former New York State Governor Eliot Spitzer. People would prefer obscure email addresses over even more obscure telephone numbers. Finally, it is easier to remember than some long-winded telephone number. And while it is true that .com implies (but does not insist) on a US focus, +16055551212 is very clearly a US number. People are more global nowadays. On the other hand, is a work address, and people change a lot. Further, people don't want some material going through work, whether because it is a waste of work time, personally sensitive or any other reason.

The real question, then, is whether any unique global identifier would work. The answer, in my opinion, is a qualified yes. I think many people would be happy to have a unique identifier, that I can simply give someone my ID, whatever it is, most likely in email format, and they can use it to get everything about me. It is qualified, because I believe people want to maintain control. I don't want every spammer to have my email address, I want business associates to have my work email and phone but not my mobile, and I may not want my home contractor to have my work number. I believe that if someone came up with a unique identifier system that could be used for real-time lookups across systems, while providing reasonable and non-burdensome access control for the owner of the data, it would likely be successful. Whether or not it can make money, and how it fits with existing social networks, is an entirely different topic.