As it currently stands, Google hands over the 'final' code for each version of Android, and OEMs and developers then spend some time customizing the OS to fit their hardware, and to create a unique and marketable flavor. That's all set to change, however.
Over the last few months, according to several people familiar with the matter, Android licensees such as HTC, Motorola and Facebook, have been asked to sign 'non-fragmentation clauses.' This new contract caveat will give Google the right to review and pass judgment on all changes to the Android OS. Two executives at Facebook say that they're unhappy that Google gets to review its changes to Android -- which is understandable, given Facebook and Google are direct competitors -- and there have also been allegations that Google is preventing some Verizon devices from shipping because they include Microsoft's Bing instead of Google search.