There’s not much there as far as big changes go, but I suspect this message really has nothing much to do with the TOU itself. The underlying point of this update and accompanying communique seems to be that Microsoft has learned that many of its users don’t have up-to-date contact information on their accounts, as it is mentioned multiple times. Fair enough, as the XBox One’s release date approaches, they would want to make sure that’s as current as possible.
So, if you’re an XBox Live user, please go into your settings and update your contact information. Or don’t.