Once upon a time, Research In Motion’s BlackBerry devices ruled what would later become known as the smartphone market. Untold thousands of businesspeople spent a healthy portion of their day tapping out messages on their phones’ tiny plastic keyboards, to the point where “BlackBerry thumb” became an actual term. And believe it or not, but there was a time when Microsoft’s Windows Mobile also occupied a healthy share of the mobile market—peaking at 42 percent in 2007, before descending rapidly over the next few years. (That same year, RIM held 35 percent of the market, according to The NPD Group.) That all changed, of course, with the rise of Apple’s iPhone and the galaxy of devices running Google Android. Now RIM is fighting for survival, with all its proverbial chips placed on the success of the upcoming BlackBerry 10 platform (slated in arrive in early 2013), even as Microsoft’s Windows Phone struggles for recognition as something other than an also-ran. But according to new numbers from StatCounter (and offered up by wmpoweruser), Windows Phone’s install base will pass BlackBerry’s by the end of November 2012, at least in the United States. While RIM draws from BlackBerry sales in developing regions for much of its support, the U.S. represents a prime market—perhaps the prime market—for smartphones. That doesn’t necessarily mean that Microsoft will overcome RIM in the longer term: whether or not it proves a hit, BlackBerry 10 could stabilize or reverse the company’s market-share decline. Microsoft’s own efforts with Windows Phone could also stall, especially if Windows Phone 8—the upcoming iteration of the platform, which shares a kernel, file system, graphics support, and other elements with Windows 8—crashes and burns on the open market. Nonetheless, the StatCounter graph neatly illustrates that longtime truism of the mobile space: that things can change fast and kings can fall. The relative market-share of iOS, Android, Windows Phone, and BlackBerry also has a seismic effect on cloud-services and apps developers, who need to decide which operating systems are worthy of their (occasionally tight) resources. Although Microsoft’s share of the mobile OS market lags behind that of Apple and other competitors, the company has managed to corner several Android manufacturers into lucrative royalty agreements, ensuring that Microsoft will make some money even if Windows Phone eventually proves a definitive flop.   Image: StatCounter (via wmpoweruser)