The growth news for smartphones in general and especially Google’s Android has been good for a long time. But some dark clouds started appeared as the holiday shopping season, usually an orgy for phone purchases, began in November.

Working off of comScore stats, Helsinki-based analyst/blogger Horace Dediu at ASYMCO reported an “uncharacteristic” slowing of smartphone growth in the period ending in November.

On the surface, things seemed fine as 1.4 million new smartphone users left behind their old dumbphones to get smartphones. That represented a 0.6 percent increase in smartphone penetration to 39.1 percent.

“The problem is that this is half the growth of the previous period,” Dediu said.

Digging deeper, he found the source of slowed growth was Android especially in the USA.

Dediu noted: “(T)he U.S. share of Android activations is decreasing. From a cumulative average of 20 percent to a recent 12 percent.”

Apple’s iPhone showed some growth. Beleaguered BlackBerry from Research In Motion remained beleaguered.

Dediu said he couldn’t explain the cause yet since seasonal factors would affect all platforms.

Not everyone read the tea leaves the same way.

ComScore finds that 234 million Americans age 13 or older use mobile devices, while currently 91.4 million own smartphones.

And within the smartphone segment, Android has come to rule the roost.

Athima Chansanchai at MSNBC had Android popping a few extra corks  over its smartphone domination based on Android owning 47 percent of the market to Apple’s 29 percent.

Looking at the same comScore numbers, Steve Kovach at Business Insider concluded that Android should be, more or less, running a victory lap: “Apple did see its smartphone market share grow a bit, from 27.3 percent to 28.7 percent in the last three months. But Google’s Android platform is still crushing it with 46.9 percent of the smartphone market in the U.S.”

This story is still emerging. Let’s see how comScore sorts out December and the whole of 2011.