According to market researchers at Canalys, Google's Android is now the number-one smartphone platform in the world, displacing Nokia's stagnant Symbian system. And though this milestone was long expected, given Android's growth, the sheer rate at which Android has risen is simply astonishing: Hardware makers sold 4.7 million Android devices in the fourth quarter of 2009, but a year later that figure rocketed up to 33.3 million units. That's sevenfold growth.

With these numbers, Android now controls 33 percent of the worldwide market for smartphones, compared with 31 percent for Symbian, 16 percent for Apple's iPhone, 14.4 percent for Research in Motion (RIM) BlackBerry, and 3.1 percent for Microsoft's Windows Mobile/Windows Phone. In the same quarter a year ago, Android controlled just 8.7 percent of the market, good enough for 4th place.

Smartphone makers shipped 101 million devices in Q4 2010, up 89 percent from the 54 million units sold in the year-ago quarter.

For Android's competitors, the news is somewhat mixed. Both Nokia (which makes Symbian devices) and Apple (which of course makes the iPhone) experienced unit growth between 2009 and 2010. But both companies also lost market share because Android grew so much faster.

Symbian unit sales jumped from 24 million units in Q4 2009 to 31 million in Q4 2010, but the market share for the system dropped significantly from 44 percent to 31 percent in the same time period. And iPhone unit sales jumped from 8.7 million units in Q4 2009 to 16.2 million in Q4 2010, but it too took a market share hit, dropping slightly from 16.3 percent to 16 percent in that time period.

Apple's strategy for catching up to Android is well established: It will open up its iPhone to more wireless carriers this year, including Verizon Wireless in the United States this quarter, and it will continue to push iPhone as the technology leader at the high end of the market. Nokia is a question mark for now: CEO Stephen Elop recently acknowledged that the company faces "significant challenges" and said a strategy change would be announced February 11. Many speculate that the company will adopt Android, Microsoft's Windows Phone, or possibly even both platforms.

Microsoft's new smartphone platform, Windows Phone, has performed solidly given consumer confusion over the devices and the challenges inherent in competing with high-quality, established players. And Microsoft has seemed to freeze like a deer in the headlights since shipping Windows Phone last fall; the company has yet to release even the tiniest of software updates since then, despite widespread problems with the software. This isn't the right message to send to early adopters or potential new customers.

Regardless, none of Android's competition has a good plan for competing in the low end of the market, and this is where Android will likely see its biggest growth in 2011. Whether anyone can face the hordes of Android devices coming to market this year remains unclear. But it's going to be a fascinating year for the smartphone market regardless.