MS, tech says "It'll just stop as if someone had pulled the plug (this is on account of how someone will have pulled the plug.) You'll get that page that says "Page cannot be displayed" until it comes back. I was going to put up a note with "We are down at the moment blah blah", but if you do that it's a big old hassle - some people get access back sooner than others and so on. Better avoided."
So that'll be interesting (not).