This has been SOP for Microsoft for a very long time. Someone else starts doing something innovative around their patch and they immediately announce some piece of vaporware that's going to take it on head to head. It used to work well when they were the biggest and the baddest on the block -- the investors would either shit themselves and shut off the funding spigot for the luckless start-up. Or, they'd go crawling to Redmond asking to be bought out and shut down.
Problem is, it doesn't work anymore because nobody is afraid of MS anymore. They are slow, reactive and out of touch. Apple's creaming the hardware space on one side of them and Google owns the Web space on the other. And both are slowly squeezing Microsoft's one pillar, the OS near-monopoly. Windows Mobile is on life support as Android and iPhone OS charge ahead. If (not if, when) those are extended onto tablet devices and if (this one's a little iffier) tablet devices truly begin to supplant laptops as the primary mode of mobility computing, MS is up the proverbial shit creek.
So, nowadays, this is pretty much just the equivalent of Ballmer jumping up and down and yelling: "We're still in it! We're still in it!"