Andy Rubin has added another response to Alibaba's Aliyun OS, after Google's insistence that Acer put the launch of its new smartphone on pause. He focuses (again) on the Open Handset Alliance (OHA), which OEMs agree to when they work with the platform, promising to keep Android a happy (and relatively compatible) platform. Amazon dodges any similar issues with its Kindle Fire tablets, because it didn't sign up to the same alliance. Rubin says that because Aliyun uses Android's framework and tools -- as well as housing some suspect Android apps (and pirated Google programs) within its own App Store -- the mobile OS "takes advantage of all the hard work that's gone into that platform by the OHA." Google's looking to protect how Android behaves as a whole, and the senior VP suggests that if Alibaba's new OS wanted "to benefit from the Android ecosystem" then they could make the move across to full compatibility. We're still waiting to hear what Acer (and Alibaba) plan to do next.