Android is open, in a sense, but it's not as clear cut as it could be
Google blocking Acer from releasing a Aliyun-based device sure isn't making Google look good. The company has now explained why it did it and, more importantly, revealed that Alibaba's Aliyun is actually based, at least in part, on Android.There's nothing wrong with that, as Android is open source, the problem is that an Open Handset Alliance member, like Acer, can't ship an incompatible version of Android.
Google has always banked on the "open" aspect of Android. Just how open Android is has been a matter of much debate. In the end, it's all down to what you call "Android."
Android itself is open source. That is to say, the core Android apps, the modified Linux kernel on which it's based, the core libraries the Dalvik Java virtual machine as well as all the core apps, i.e. the dialer, the browser, the email app, the calendar and so on, are all open source.
Anyone can use them and if you compile the Android Open Source Project (ASOP) you get a fully functional mobile operating system. But you don't get the "full" Android you get on an officially sanctioned device.
Still, in this sense, Android is open. Plenty of phone and tablet makers have used this code base to create their own take on Android.
Amazon for example took the core Android and built it into its Kindle Fire devices. The Kindle Fire OS, despite being based on Android, bares no resemblance to it, it looks and works very different.
Amazon's take is one of the more extreme modifications. Amazon doesn't use the Android name anywhere and tries to get as far away from it as possible.
At the other end of the ASOP spectrum are numerous "no-name" Chinese phone makers which simply grab the Android source, bundle some of their apps with the OS and ship a myriad of phones with it.
None of these though have anything to do with Google. Google does not need to approve of this, it doesn't even have to know. So, again, in this respect, Android is very open.
But there is a catch. No one simply grabbing the Android source code can use any of the official Google apps or the Android trademarks. This means, no built-in Gmail, no Google Search, no Google Maps, no Google Chrome and, more importantly, no Google Play.
None of these devices can access the official Android app store. None of the Google apps are open source and to get them you have to have a direct relationship with Google. Specifically, you have to be part of the Open Handset Alliance.
Being a member means you get access to Android code sooner, you can use all the Google apps, you get to say that your phones or tablets run Android and so on. But it's not all perks, access to the apps and the brand means that you can't go wild on changes in Android.
You can install any apps you want, customize the look and feel however you want. But you can't remove the Google apps and you can't alter the underlying software in a way that would make it incompatible with any of the existing third-party apps.
There is a good reason for all of this, and it's what Google is reiterating these days. Forcing this manufacturers to comply with these rules means that apps will work on any device. Android fragmentation is bad enough without incompatible flavors of the OS running on any device.