It can be scary mustering developer support for a brand-new app platform -- just ask BlackBerry. Microsoft may feel slightly relaxed, then, if MetroStore Scanner's unofficial estimates are on the ball. It sees over 50,380 active Windows Store apps as of this writing, which isn't bad for a shop that reportedly had less than half this amount back in November. Whether or not you consider it progress compared to the rest of the market is another matter: the tally is a big leap over the estimated 14,000 apps in the Mac App Store, but it won't make either Apple or Google break out in a cold sweat when compared against the six-digit app counts of their mobile app stores. Microsoft currently declines to confirm the numbers, although the company tells us that the app count may vary from country to country. For now, it's safe to presume that a fair number of app writers are onside with Microsoft's tile- and touch-driven vision of the future.