The third ecosystem. What are the odds?

The latest survey from ComScore breaks down the installed base of specific mobile platforms in the US. Tracing the data over time shows the following charts:

In the last month Android gained about 2.9 million users, iPhone 1.3 million, Blackberry lost 530k users and Windows held on with a gain of 132k. Other platforms had a net loss of 95k users.

In the last 12 months, Android gained 25 million users in the US. iPhone gained 9.5 million while Blackberry lost 3.2 million and Microsoft lost 1.6 million. Other platforms had a net loss of 1.2 million.

The total net gain of smartphones was about 29 million new users.

RIM switched from being a consistent net gainer of users to a consistent net loser of users in October 2010. Windows Phone is showing signs of holding the line on user base erosion but share remains below 5% (now at 4.7% vs. 4.6% last month). To put the mountain-sized hurdle in perspective, Android now has 7 times more users in the US while iPhone has about 5 times more. To become the largest mobile platform in the US, as some analysts are predicting, Microsoft has a 12:1 disadvantage that looks to continue to grow.

Those are some pretty tough odds.