Once upon a time, Windows-based phones were a solid participant in the smartphone market, back in the days when Blackberry reigned supreme and Apple made Macs and iPods. Since the launch of the iPhone, however, Microsoft’s smartphone market share has suffered considerably. With the launch of the Windows Phone 7 operating system last year, however, Microsoft began making its way back into the market. Since then, the phone has carved out a respectable niche for itself.

Now, All About Windows Phone has released some interesting data concerning the Windows Phone Marketplace. It seems the Microsoft’s app store hit a major milestone last week: over 50,000 have now been submitted to the Windows Phone Marketplace (though not all are available for download in all markets).

It seems that a large part of this growth has come in the last month. While it took a full year to reach 40,000 apps, the final 10,000 were submitted in the last month.

Perhaps the most interesting aspect of this data is how it stacks up against other mobile app stores. All About Windows Phone compared the Windows Phone Marketplace’s growth to that of four other markets: the iOS App Store, the Android App Market, Symbian, and BlackBerry. Of the four, only Apple reached 50,000 apps faster than Windows Phone. While it took Windows Phone about 13 months to get to 50,000, Apple got there just a couple months faster. Meanwhile, Android took over a year and a half to get to the same point, while Symbian and BlackBerry took well over two years each.

This suggests that while Windows Phone’s market share is still quite small (late this summer Gartner’s research showed it at 1.6%), Windows Phone is seen as a viable platform for app developers. If that’s so, then we can probably expect to see Windows Phone continue to grow, perhaps to the point of becoming a solid competitor for Apple and Android phones.

What do you think? Can Windows Phone challenge Apple and Android? Let us know in the comments.