One device.... multiple users. Identity crisis?

Various issues cropped up in last week's IMS Services Forum in London that pointed out the difficulties in translating mobile-sector concepts to the fixed-broadband world. Given that the emergence of quadplay services, FMC and IMS are bringing these closer together, some problems are emerging.

One such problem is the notion of identity. I'll be making another post about the challenges posed by anonymous prepay users in an IMS world. But even more general considerations about identity are likely to crop up.

In the mobile world, it is generally fair to assume that the person using a handset is its notional "owner". It's a personal device, usually (outside corporate accounts) with a personal billing relationship, typically a SIM card, and all the "personalisation" that goes into a phone. If someone's using the phone, 99% of the time you know who it is - or, at the very least, it's the same anonymous person consistently. Identity = normal user, to a reasonable approximation.

Conversely, a TV or (to a lesser degree) PC is "communal". There's no SIM, no personalisation, no tracking of who is watching / using it. It might be one person focusing on it intently, or it could be switched on in the corner during a party for 50 people. And there may well be multiple TVs in the house - possibly switched on when nobody's actually watching. (Don't even begin to suggest using NFC or some other similar approach to using your phone to "sign in" to a TV).

So, assuming you've got an IMS, with its wonderful HSS subscriber data store.... how do you deal with this? How do you link a household, non-personal, one remote-control, IMS-TV subscription to multiple, personal mobile accounts? Even leaving aside the privacy issues around such farcical notions as SMS-to-the-TV-screen (thanks Martin), this presents some pretty unpleasant issues for the billing & charging systems. I reckon it should make the supposed "single sign on" notion pretty impractical in many cases too.

I'm not an expert on identity technologies. But I know enough to recognise a minefield when I see one.