February 06, 2005
Telephone numbers versus URIs
Chris Holland does a good job explaining why SIP URIs matter. I read his blog entry a few weeks back. Since that time, I have been thinking about URIs versus numbers in telephony, with regard to usability.
One problem with URIs is that they are hard to enter if you use a small keypad.
One advantage of URIs is that they can be easy to remember. But that may not always be the case. In a crowded namespace, one can not always choose an easy-to-remember URI. And there are those individuals who choose unusual aliases that have nothing to do with their names.
If you must leave someone a voice mail message with your phone "address," which would you rather say? A number or a URI? (I think the number is easier: "Please call me at 5-5-5 1-2-3-4." versus "Call me at doug sauder -- that's spelled S-A-U-D-(as in danny)-E-R -- at eye pee tell dot org." )
So, it seems that URIs may be easier to remember. But most of the other factors weigh toward numbers, strange as that may seem. For most people, numbers are the clear winner. Ordinary people understand them, and they just work.
If URIs are like email addresses, then we won't type them. Instead, we will choose them from an address book. No problem. But what if the phone you use is shared by many individuals? That means the address book won't be stored in the phone's memory. Could the address book be stored somewhere in the network, accessable from any future phone? That may be possible, but there are security risks.
If numbers remain far more usable than URIs, that presents a serious problem to the long-term future of alternative communications, which includes such services as Skype. And it's great for legacy phone services. At issue is control of the namespace. Anyone could set up a SIP server and dole out SIP URIs. It's much harder to get an allocation of PSTN numbers.
Posted by Doug Sauder at February 6, 2005 12:20 AM