As Android officially outstrips its smartphone competition in the US for the first time, underwhelming Motorola Xoom adoption tells a different tale for Honeycomb.
Google's success in the smartphone arena shows no sign of abating, but as Android celebrates its achievement in attaining the highest percentage share of smartphone subscribers in the US for the first time, lower (and slower) than expected sales for Motorola's Xoom tablet stateside (which features Android's tablet OS, Honeycomb) indicate how distinct the smartphone and tablet markets are - and demonstrate that Android's seemingly unstoppable growth does not yet extend beyond the smartphone sector.

Android, on the smartphone at least, shows no signs of slowing down. (Credit: comScore)
Last week market researcher comScore released its latest quarterly mobile market share
figures, revealing that Android, for the first time, is the dominant smartphone platform in the US. Over the period December 2010 to February 2011, Android's share of the smartphone market grew to 33% (up 7%), knocking BlackBerry off its perch to 28.9% (down 4.6%). Apple's iPhone remained fairly steady in third place at 25.2% (up just .2%), with Microsoft and Palm both losing moderate ground to hold 7.7% and 2.8% respectively.
Going off these numbers, it seems one in every three smartphone users in the States is currently using Android, and that figure is still growing (and then some). Indeed, if you look at the trajectory in the graph above (based on the same comScore data, but running January 2010 through January 2011), Android's smartphone growth doesn't look like stopping (or even slowing) any time soon. But while Google may be celebrating these figures, another set of numbers is giving Android cause for concern.
Reports of initial disappointing sales for Motorola's Xoom tablet, the first (and still only) US tablet to run Android's tablet-tailored 3.0 Honeycomb software, suggest that Google may have to be patient if it's hoping for a repeat performance in the tablet market. Deutsche Bank is claiming that only 100,000 Xoom units have been sold since the device's launch on February 24. Whilst that's a generally admirable effort for a new consumer gadget, it contrasts sharply with the original iPad's early sales achievements: 300,000 on day one, 500,000 in the first week, one million by the 28th day (you get the picture). And the iPad 2 is selling at an even faster rate than its predecessor.

Movement amongst the top five smartphone platforms in the US. (Credit: comScore)
To be fair, Motorola's lower than hoped for sales with the Xoom to this point don't necessarily signify that it's a failure (for either Motorola or Android). And given so many other tablets featuring Android will be released within the next six months, revisiting the figures further down the track will provide a much clearer picture of the tablet OS's vitality (and positioning).
So it's still extremely early days for Android in this landscape; it took Google two and a half years to get where it is today in the smartphone market. But these numbers do serve as a startling reminder that, amid all the attention being lavished upon the Android tablet festivities this year, Google still has a long, long way to go in replicating its success against the iPhone (et al) with its foray against the iPad.