Cortana ...
Go and delete yourself.
I'm sorry Dave I can't do that.
IMHO, this is another example of Microsoft fiddling while their empire burns all around them. (see icon)
This tool might be useful on a phone (at least that's what the adverts tell us) but on a desktop? WTF?
At least Apple haven't unleased Siri to the Mac users yet (AFAIK). now that would result in a lot of Fanboi gnashing of teeth and a hundred blog posts about ho to remove it.