In a recent tally of mobile OS market share estimates from Canalys, the market was organized by OS vendors. The number of devices sold by operating system vendor includes as many OS’s as each vendor may supply.
For example, Microsoft licensed two different OS’s during the period: Windows Mobile 6.5 and Windows Phone 7. Nokia also offered multiple versions of Symbian, which have varying degrees of inter-operability.
Fragmentation is not a new subject as OS licensing models have been ripe with it for as long as they existed.
What I want to draw attention to is the concept of Google as “vendor.”