An analyst note released by research firm IDC yesterday points out that in the nearly two months since Windows Phone 7's retail release, the Windows Marketplace has swelled to 4,000 applications -- a number that the Android Market took five months to reach. That's impressive, no doubt, and the analyst behind the numbers notes that he "would not be surprised if Microsoft had the third largest app portfolio in the industry by the middle of next year." Now granted, hitting number three would take very little effort on Microsoft's part -- they'd just have to beat webOS, BlackBerry OS, and Symbian, none of which have sparked iOS- or Android-like levels of developer interest. So beyond that, what does the growth mean? Read on!

[Thanks, Stephen]

Realistically, not much. On a fundamental level, app store success and platform success aren't yet one and the same -- look at BlackBerry, for example -- but beyond that, there are several things to consider here. Android launched on the T-Mobile G1 alone, which means that for most of the period IDC mentions, the Android Market was really more of the "G1 Market" than anything else: one device, one carrier, one country. It wasn't until the first half of 2009 that additional markets and devices came online, and even then it was slow going -- typically one device on one carrier per market. Windows Phone 7's had a moderately more well-supported and well-rounded launch with devices from HTC, LG, Dell, and Samsung reaching multiple carriers in multiple countries across North America and Europe within a few days of each other. Sure, you could use the iPhone as the counterexample here; Apple saw explosive App Store growth with just two devices (the original and the 3G) on a handful of carriers around the world, but by the time third-party apps were enabled, the company had already assembled a big installed base of users hungry for more functionality.

And let's not forget Redmond's time-honored mantra: "developers, developers, developers." Microsoft is famously great at supporting its developer community, and it did a commendable job parlaying that developer base into its Windows Phone 7 launch by utilizing tools and languages that those developers already knew. Clearly, throwing together an app for a new platform is a much easier endeavor to justify when you don't need to crack any new books or learn any new development environments -- and indeed, an existing .NET or XNA developer can roll a WP7 app with very little ramp-up time. On the Android side, sure, the syntax is familiar to Java developers, but the libraries and constructs were all new; mix that in with an ultra-limited launch in the early months and you've got a recipe for a slow-growing Market.

Bottom line? Both these platforms are going to be successful, but for the Windows Marketplace to overtake the Android Market is going to take nothing short of a miracle -- and interpreting IDC's data any other way would be a reach.