Their privacy statement says they will. You voluntarially give up privacy to use Google and Microsoft apps.

I would like to ensure my communications are private and stay that way. Not later dredged up, quoted out of context or leaked to competitors. Or in a more general way mined for someone else's use in profiling groups to manipulate in future advertising campaigns. If Google, Microsoft, etc are involved you can bet they will vigorously support only virtual privacy. Anyone know of "Skype like" apps that support privacy in communications for the masses? (ie not just for the tin foil hat people)