Re: What is the benefit putting a cloud in the middle?
MS is not called SLURP for nothing. They'll more than likely grab information on all persons involved in the call and feed it to their Ad Agency Clients. Then you will get popups (different at each end) inviting you to 'click here to get more information on XXXXX. We noticed that you were talking about it just now'.
Simples really. MS (like most companies) don't do things out of the kindness of their heart.