It's an open loop system, presumably to save mass.
Slashdot videos: Now with more Slashdot!
We've improved Slashdot's video section; now you can view our video interviews, product close-ups and site visits with all the usual Slashdot options to comment, share, etc. No more walled garden! It's a work in progress -- we hope you'll check it out (Learn more about the recent updates).
Cloud in this case appears to mean "Microsoft hosted datacenter".
RPC-over-HTTP has been around for awhile now and should work fine with this 'cloud' service. They didn't seem to imply the Office apps were going cloud, just server side.
Link to Original Source