CardSpace's Privacy Problems
From Ben Laurie:
If Microsoft are really serious about providing “non-audit” (i.e. unlinkable) modes for CardSpace, then they need to get with the program and stop trying to pretend that they can do this with RSA signatures. Its a shame that they’re going to such lengths to make CardSpace good but can’t quite seem to go the last mile and make their claims actually true. Perhaps they don’t want to?