Is that supposed to be funny? No Jellybean devices have shipped to the general public yet the source has been released. Also, AOSP is not a sub-set of Android, AOSP is Android. Anything else is an add-on including the Google Apps.
Your snarky comment isn't even accurate. The only thing not released in AOSP is Google's propreitary APKs of the Google Apps (Market, Gmail, etc). One can build AOSP and have Android almost identical to Galaxy Nexus or what not. A small zip later, and it's nearly byte for byte identical.
You also forgot the proprietary drivers needed to actually use almost any of the devices on the market (including Google's own that they sell directly now).
While the original poster was being somewhat disingenuous, let's be honest here, Android isn't a completely open platform. To obtain full functionality from Android devices requires more than what Google distributes source code for.
I say this as a somewhat angry and disappointed Android developer :-(
Android is the software that runs on many devices. Full functionality is the responsibility of the hardware manufacturer to offer compatible drivers and software to enable the full functionality you're seeking.
The entirety of the OS is there for anyone who wants to hack together the functionality that you're "missing" but the OS is complete and open so far as I can see.
How is that Google's fault though? How many modern mobile devices have completely open drivers including wifi, camera, accelerometer, bluetooth, and GPU? Exactly none. Even the raspberry pi has binary blobs. It doesn't make sense to blame Google for not being able to provide what doesn't exist.
I'm not blaming google; I'm just suggesting that Rubin's snarky twitter post about the "definition of open" is somewhat misleading.
Put simply, I'm just trying to point out the sad state of affairs.
Android is primarily run on Phones, but you can't actually use some of them as a Phone if you build AOSP and install it because some of the binaries required for the phone functionality can't be distributed.
That's my point. It's misleading to say "here's an open phone OS" -- when you can't actually use it on your phone, because the things that make your phone work as one aren't open and can't be redistributed.
An open platform doesn't do much good if you can't actually use it on hardware with full functionality.
As I said before, I'm just a disappointed and somewhat angry Android developer, somewhat. Google could have done a better job here and made life easier for me and other developers.
This is true of every smart phone in existence. Period. Even when OpenMoko tried it, they still had binaries. Luckily they were given permission to redistrib the binaries.
http://source.android.com/about/index.html