Android is once again the star of the show in this month’s Millennial Media “Mobile Device Index.” We regularly cover the Millennial Media SMART report here at SiliconANGLE, because Millennial continues to be the largest independent network for mobile monetization, and as such always has interesting insights to show us when they tally usage. This month, though, they’re debuting the Mobile Device Index, and additional report that profiles handsets and mobile devices specifically (including, yes, iPads).

Some observations after going over the data:

– Google Android’s growth continues to be impressive, growing 72% month-over-month, but still falling significantly short of the AdMob 40% marketshare reports, clocking in at 6% (make sure to check out Jeff Nolan’s ANGLE on the wide discrepancy).

– Android’s new marketshare is coming from Hiptop OS, Apple and other lesser OS’s.

– Despite the release of the iPad and the hype around iPhone, this is one of the first months in recent memory that Android usage has bit into Apple usage, and their marketshare actually decreased.

– Windows Mobile and RIM have held steady (and seen slight) increases in marketshare, but Palm’s webOS took a severe beating, dropping two of their three marketshare points from last month.

We’ve been observing this growth a while, here’s our ANGLE:

Android still isn’t necessarily warring with Apple (if they were, you’d see a lot more graphs that supported the AdMob point of view, where Apple loses half their marketshare and Android takes it up).  That simply isn’t happening, mostly because the mobile phone space isn’t a world where customers are generally allowed to switch, and when they do it’s not a decision taken lightly (penalty fees! extended contracts!).

Android is opening up new markets. The data released in this report isn’t exactly apples to apples to last month’s SMART report, but there’s clearly significant growth in smartphone usage. Last month, Millennial reported smartphones as accounting for 45% of mobile impressions. This month, they account for 65%. That growth is happening somewhere, and it looks like it’s happening mostly in Google’s court.

As I said last month, “if you’re in the mobile space and you’re not paying attention to Android, you’re not doing your job.”

[Editor’s Note: Millennial Media is a sponsor of SiliconANGLE. –mrh]