At the recent Gartner Identity & Access Summit, analyst Earl Perkins spoke of the potential for Facebook to be used as an enterprise IdP. I'd like to see these sorts of speculations dampened a little by filtering them through the understanding that identity is a proxy for relationship.
Here's the practical difficulty that shows why we must reframe what we're talking about. If Facebook were to be an Identity Issuer, they would have to be clear about what enterprises really need to know about their staff, customers, partners and so on. There is no standardised answer to that; every business gets to know its people in their own peculiar ways. Does Facebook with its x-ray vision into our personal lives have anything to offer enterprises? If we work out which assertions might be vouched for by Facebook, how would they be underwritten exactly?
And I really mean exactly because liability is what kills off most identity federations. The idea of re-using identity across contexts is easier said than done. Banks have tried and tried again to federate identities amongst themselves. The Australian experience (of Trust Centre and MAMBO) was that banks find it too complex to re-use each others' issued IDs because of the legal complexity, even when they're all operating under the same laws and regulations! So how on earth will business make the jump to using Facebook as an IdP when they have yet to figure out banks as IdP?
The old saw don't "Mix Business And Pleasure" turns out to predict the cyber world challenges of bringing social identities and business identities together. I have concluded that identity is metaphorical. Each identity is really a proxy for a relationship, and most of our intuitions about identity need to be reframed in terms of relationships. We're not talking simply about names! The types of relationship we entertain socially (and are free to curate for ourselves) may be fundamentally irreconcilable with the identities provided to us by businesses as a way to manage their risks, as is their prerogative.