QUOTE(nuke field ET @ Dec 24 2007, 08:51 PM)

How the hell are you supposed to know someone else's "windows live ID"?
I guess that you could always message someone and ask them their e-mail address. Even if you were trying to make it a surprise, asking someone for the MS e-mail address related to their Live account wouldn't automatically give you away.
One benefit of this system is for someone that wants a small number of points for a one-time purchase, doesn't have a credit card, and doesn't wany to buy $20 worth. They just pay their friend w/ the credit card. Or if someone says "we should play this arcade game online together, here I sent you the points to buy it". I think that it's a pretty good idea.