Today the Wall Street Journal’s Walt Mossberg interviewed Microsoft’s Joe Belfiore on the state of Windows Phone 7.  Owen Thomas of Venture Beat sums up what most people are thinking about the interview.

I could write a long post about all the things that Microsoft executive Joe Belfiore, director of the Windows Phone program at the software giant, said at the D: Dive Into Mobile conference in San Francisco.

But it’s mostly stuff you’ve heard before. Far more important was what he didn’t say: How many phones Microsoft has sold since Windows Phone 7’s splashy launch last month.

Without sales figures, Microsoft’s mobile hype is all talk. The company never hesitates to brag about how many Windows operating systems licenses it’s sold, after all.

In most cases I’d agree with this sentiment but I think Microsoft is an exception.  The way I see it numbers matter for two reasons. 

1.  They’re an indication of the number of apps that will be built for the platform

2.  They’re an indication of whether the platform will survive at all (since no one wants to be stuck with a phone built on a defunct platform).

But neither of those concerns really apply to Microsoft.  On the issue of Apps they’re clearly willing to spread money around to get the best apps ported to Windows Phone 7.  So even if they sell very few Windows Phones they’ll have the hottest apps.

On the platform’s survival I think any strategic read of the situation indicates Microsoft CAN NOT lose this battle.  They need a presence in the consumer market and they know it.  Right now the only successful consumer product they have is the XBox line and that’s just not enough to fuel future growth.  Yet they’ve already failed at just about every other consumer Endeavour.  Tablets, the digital living room, automobiles (remember AutoPC) and so on.   

Microsoft needs a smartphone win.

At the same time they can’t start over again on their phone platform without completely compromising their credibility.  Windows Phone 7 IS their “start over” and no one’s going to allow them to do it again. 

So while poor sales aren’t great they don’t mean the same thing for Microsoft as they would for a company like pre-HP Palm.  Microsoft’s deep pockets make a difference and will keep them in the smartphone market to the bitter end.