This is a little cynical, but I’m thinking that Yahoo would not have started the Open ID drive had they not been having difficulties.  Being in trouble encourages you to mix it up a little, and I’m (cynical) thinking that grasping at straws brought on this move.  Any way you slice it it’s good for the web.  I was ragging on Microsoft’s Phil Holden over a year back to do something similar…great to see the 800 pound gorillas getting on this thing.