Infocard (now called CardSpaces) is Microsoft's new entrant in the identity arena. Right now it's not to be confused with Microsoft Passport, which may originally have been conceived as your universal identity card for all websites and services, but certainly never ended up as that.
CardSpaces however, is definitely seen as the beginning of the end of the username and password.
CardSpaces is different though on a number of levels. The first, and probably most reassuring one, is that your personal data and the cryptographic keys to get at that data will not reside solely with Microsoft. Instead, it will rest with a number of objective, trusted third party providers of certificate and encryption services.
The second is the level of integration with the browser and operating system, and therefore how seamless it could be for users to use it on sites that subscribe to the service as it doesn't require a password to operate it.
But there's no way I'm going to get into the debates on a) Civil Liberties, or b) Security on who could make use of your infocards on your PC whilst you're away from it. I'll leave that one to rumble on with others because I'm sure that there are answers to them that I don't know about yet.
Instead, I'm more interested in what users will make of them. They are visualised as 'cards'; literally, in a pop-up window in which you select the infocard you want to use.
The choices you have though are pretty vast, and that's where I predict a level of friction with users.
An Infocard is modal. i.e. it can be a number of things depending on its context. It can simply be a set of personal data as cut-down as your email address and city of residence; or it could be a full set of details, coupled with your credit card data. It could also be the details of a particular discount card or loyalty scheme to which you subscribe.
So, you could use different Infocards to register for membership of a website, to pay for goods, or to put your Virgin Atlantic Flying Club number into your Hertz Car Rental booking.
Getting your head around what an Infocard is, is difficult already, and I suspect that these multiple uses will serve initially to help confuse the situation and therefore to make adoption by end users pretty slow.
Maybe Microsoft should encourage an adoption strategy that gradually introduces consumers to the concept, using it in a single conisstent fashion (e.g. to hold name and address details), before moving it on to take full advantage of the system's capabilities.