On March 10, analytics company ComScore published its latest statistics on smartphone operating systems in the United States. Its report, which covered the three-month period between October and January, contained some good news for three companies: Research In Motion (makers of the BlackBerry), which rose 1.7 percent to take 43 percent market share; Apple, which rose 0.3 percent for 25.1 percent market share; and Google, which rose 4.3 percent for 7.1 percent of the pie.

By contrast, two companies posted miserable figures. Palm fell during that period by 2.1 percent, thudding down to an overall 5.7 percent market share. And Microsoft tumbled 4 percent, dipping from a 19.7 percent market share in October 2009 to 15.7 percent by January.

Windows Mobile 6.5, released in October 2009, was supposed to be a sort of placeholder, retaining Microsoft's market share in the smartphone space until Windows Phone 7 Series could hit the market. Windows Mobile 6.5's interface was supposed to be leaner and meaner, the functionality more robust thanks to the introduction of Windows Marketplace for Mobile, the company's entry in the mobile-applications arena. But people obviously didn't gravitate toward the offering in the way that Microsoft had hoped.

But now Microsoft finds itself in a bit of a quandary. Devices in the Windows Phone 7 Series will be released sometime near the end of 2010, which is months away. In the meantime, Microsoft has indicated that previously built Windows Mobile applications will not run on its new operating system, while rumors are circulating that even the new-and-nifty HTC HD2 running Windows Mobile 6.5 won't be upgradable to Phone 7. That lack of an upgrade path, combined with the delay in new devices coming onto the market, could prophesy a continued slide in Microsoft's smartphone market share for the balance of the year.

Who wins in that situation? While Apple and RIM experienced relatively small gains, Google Android rose precipitously--doubtlessly nipping away a chunk of Palm and Microsoft's respective market shares in the process. If that rise continues, Microsoft could launch Windows Phone 7 Series and immediately find itself in a tooth-and-nail battle to hold its third-place position.

Since people seem to be obviously shying away from Windows Mobile 6.5 (which rumors suggest will eventually be rebranded, along with the rest of the Mobile franchise, as "Windows Phone Classic"), the pressure only increases on Windows Phone 7 to be a hit among both businesses and consumers. What I'm interested in hearing from you is, Why do you think Microsoft experienced that 4 percent decline, despite the push behind Mobile 6.5?