Tim Bray, Android’s Compatibility Program Manager:
Literally before the close of business on the same day we announced Android (4:46pm to be precise), I saw the first article about Android “fragmentation.” The first day wasn’t even over yet, and the press had already decided that Android would have a “fragmentation” problem.
The thing is, nobody ever defined “fragmentation” — or rather, everybody has a different definition. Some people use it to mean too many mobile operating systems; others to refer to optional APIs causing inconsistent platform implementations; still others use it to refer to “locked down” devices, or even to the existence of multiple versions of the software at the same time. I’ve even seen it used to refer to the existence of different UI skins. Most of these definitions don’t even have any impact on whether apps can run!