There are two articles related to Mobile OS that caught my attention. This one, in Ars Technica, shows that, for the first time, the total number of iPhone users have passed the total number of Windows Mobile users. This one, over at CNN Money, shows the growth of Android-based devices. Clearly the flat Android line in the first article will change as 1.5+ and 2.x-based devices enter the marketplace and start gaining in installed base.
This is significant in a number of ways. First, installed base is a key factor in the development of the "ecosystem" of a device. Apple, which has locked down the hardware as well as the OS on the iPhone, enjoys an unrivaled hardware ecosystem from third parties. By tightly controlling the application environment, they maintain a strong grip on the app store, which enables them to monetize this very profitable aspect of the iPhone ecosystem. Because of the size and momentum of the installed base, they will attract more applications developers.
Android does not have the hardware control and has a more open approach to the app store which does not lend itself to monetization in the same way. However, the more open approach may attract more innovative app developers. There is clearly momentum in the Android OS camp, even if the installed base is lacking at present.
Carriers have an interest in minimizing the number of mobile OSs they support. Adding a new OS is costly because the features and services of the OSs must be tested with the network and supported by the carrier after the device is released. Thus, OSs with little installed base or momentum are at risk of losing their sponsors (the carriers) which leads to a self-reinforcing downward spiral in their ecosystem. Thus, the stakes for Microsoft in its Windows Mobile 7 (due in 2010) could not be higher; for that matter, the same is true for Palm's WebOS. Failure to attract a user base means failure to build an ecosystem.
This creates a high hurdle, but it is not insurmountable. At one time, the Palm OS was the standard with a huge catalog of applications; it is no longer so dominant. Thus, dominance is not permanent even if it can be a huge advantage in the market place