Windows CardSpace (Pro's and Con's)

I just noticed the "Windows CardSpace" option in Control Panel. I setup a Personal Card but have not used it yet.

I was wondering if any of you have used this feature in Windows 7 yet. And if so what you thought about it. Is this a feature you see yourself using or if you prefer not to use it.

I've not used it yet myself, but it looks like an interesting identity mangement tool. I'm also interested to hear some people that have used it

There's more information here for those that want to read about it : http://en.wikipedia.org/wiki/Windows_CardSpace