Tim Bray has a post up about numbers, and this began as a comment but grew a little too long.

I once described telephone numbers as ‘the original digital identity‘. The trouble is that for way too long they were associated to land lines (and hence geographic locations) and then mobiles came along and tied them to devices.

I began an experiment a few years back of having ‘one number’ – a single point of entry that would find me wherever I was and whatever I was using. It mostly works, but there are cultural and economic issues that get in the way. People don’t expect to reach you in the US when they dial something beginning +44 (and may not respect the time zone that you’re in). Similarly some don’t like being hit in the wallet for dialing internationally (especially when EU style mobile termination charges creep into the picture).

As I can’t get Google Voice I’ve been an enthusiastic early adopter of Ribbit mobile (which does much the same job, and is reckoned to have the edge on voicemail transcription). My ‘one number’ is a SkypeIn number that I point at Ribbit, which then finds me on mobile, office or ‘home office’ extensions.

The home office piece is probably the most interesting. I like to use a headset, so I got a Plantronics T20 which gives me two lines – one connected to the regular home analogue line, and the other connected to a SIP ATA. The ATA then connects to SIP Sourcery, which gives me a Ruby dial plan that mediates between a SIP connection to Ribbit and another to Voicehost (our office VOIP provider). I could add others such as LocalPhone to get some least cost routing magic, but since most of my international calls are to the US, which Ribbit handles well, I’ve not been sufficiently motivated yet.

Of course like with any digital identity after some time we discover that we’d like to have different personae. In this case that means different numbers for different purposes – the ‘family’ number that will ring your mobile even if it is 2 in the morning, the +1 entry point for business contacts in the US etc. All the pieces to do this are present today, they’ve just not been joined up into a user friendly service yet.