They are deriving revenue from the data they collect from users of the operating system. I'll speculate here a bit. Once they have hit the desired saturation point, then they will switch to a annual rental fee for the operating system. For businesses, it will get marketed as a support fee.
MS wants a big chunk of the google money making scheme I would guess. To harvest information like google does then market that is where the money is I would think.
They seem determined to kill off the PC with this crap.
