comScore published the latest data regarding US smartphone installed base. To summarize:

• Penetration reached 37.4%, an increase of 2.9 million or 1.24 points of percentage
• Approximately 650k consumers switched from non-smart to smartphones every week during September
• Based on trailing average of six months’ growth, 50% penetration will be reached by end of September 2012, though the trend is for accelerated adoption (see chart below)

Of the platforms available, Android reached 39 million users, RIM 16.5 million, Apple 24 million and Microsoft about 5 million. Smartphone non-consumers dropped to 147 million. Among platforms, here are the shares and total users:

Android and iOS have continued to increase consumption fairly consistently while RIM has moderated user losses. Microsoft has also shown the fourth consecutive month of usage increase having increased users by 440k since May. The new Windows Phones seem to have at least stopped erosion of user base though that base is still nearly a third of RIM’s.

Overall, smartphone non-consumption continues to be the largest competitor though one which is steadily losing.

The Blue Ocean is still HUGE. For all that we (justifiably, more on which below) talk about who among Apple, Google, RIM, Microsoft et al. is winning in smartphones, the biggest opportunity remains the Blue Ocean of getting smartphones in the hands of non-smartphone users. (This is true of the US, but also very true of developing markets where the shift to mobile is enormous.)