As MobileTechWorld notes, Apple has sole just over 51 million phones since its launch almost three years ago, but you have to remember that in the US, it is only on one carrier and is basically one device with a few different memory configurations. Microsoft, on the other hand, will be on several carriers and will also have several form factors, or two anyway, one with and one without a QWERTY keyboard. I'm still not sure that will be enough though for Microsoft to move the number of devices it is projecting.
Like Apple, Microsoft is tying its phone into its music service and desktop application, Zune. In fact, Engadget is reporting that the Zune Pass service may have a $5 price drop, down from its current $14.99 per month plan. With a Zune Pass, you can download just about any music track to your Zune or other Zune enabled device, like the Kin or WP7. The Zune Pass really hasn't done much to move the needle in terms of who has a Zune vs an iPod/iPhone, but so far, the Zune has been a North American device only. Perhaps by going global, as WP7 will be, along with this price drop, it could sway a few million users a year away from an Android or iPhone device.
Microsoft has put itself out there with this forecast. Anything short of around 15 million devices will be looked at as a failure compared to this aggressive prediction. By this time next year, we should have a clue as to whether WP7 sales are sizzling, or fizzling.
Updated: It turns out that the slide touting 30 million Windows Phone 7 devices was wrong. It was based on an IDC forecast which was actually 32 million devices in 2011, but it wasn't just Windows Phone 7. It was all Windows Mobile based devices. If you'll recall, with the coming of Windows Phone 7, Windows Mobile 6.x doesn't die. There are still markets that will use that platform, especially on industrial devices, but I'd expect we'll still see some low end WinMo 6.x devices from carriers through next year. Think 32 million is still too much for both Windows Mobile based platforms?