There is absolutely, positively, certifiably no way this is even close to true. Did the people are bloomberg even look at Microsoft's figures, or were they too busy counting the cash MS sent over?
So either the total is more than 100% market share for the 3, or those numbers or wrong.
Edit: added "in 2012" for rackspace financials
> Microsoft’s $1 billion sales figure includes Azure, as well as software provided to partners to create related Windows cloud services, Anderson said in an interview
That is a really vague statement that could mean all sorts of things (Office 365, Windows Server licensees, etc).
The more surprising thing to me is that Microsoft isn't burying Amazon. But give them 2 years.