writes "Galen Gruman writes about the dark side of the recent flood of Android smartphones: versions run amok. 'That flood of options should be a good thing — but it's not. In fact, it's a self-destruction derby in action, as phones come out with different versions of the Android OS, with no clear upgrade strategy for either the operating system or the applications users have installed, and with inconsistent deployment of core features. In short, the Android platform is turning out not to be a platform at all, but merely a starting point for a universe of incompatible devices,' Gruman writes. 'This mess leaves developers and users in an unstable position, as each new Android device adds another variation and compatibility question.' In the end, Google's naive approach to open sourcing Android may in fact be precipitating this free-for-all — one that might ultimately turn off both end-users and developers alike."
As reader donberryman points out, you can even put Android onto some Windows Mobile phones