@Tidbits I know you already know this, but here goes:
AOSP: Android Open Source Project. Everyone can build out their own "phone" using Android. Google leads this project and we can probably say that it promotes it the most in its purest form using it's Nexus line of devices. GApps is google property and not part of AOSP. Any manufacturer who wants Google Play, GApps integration needs to license it from Google, has nothing to do with AOSP. Since Google leads AOSP, and their Nexus line of devices provides the most convenience when it comes to building your own "image" they provide specific instructions on how you can do it. Also this keeps them from getting into licensing trouble. That's the major reason why all their GSM variants are AOSP supported and 4G/LTE are not. They are however trying to make all of Nexus AOSP supported. Good example of that is the recent re-inclusion of Nexus S4G. Also noteworthy is the fact that on AOSP Jelly Bean has more binaries available for the VZW Galaxy Nexus than ICS.
Nexus: Line of devices that Google develops in partnerships with major vendors (HTC, Samsung, ASUS so far).
ADP 1 & 2: Pre-date Nexus line of devices were purely developer phones specifically created to fill the void where Android can be nurtured in a time when no major manufacturers were yet making Android handsets.
Nexus One: Primarily release to showcase Android in it's "purest" form without any major re-skinning or customizations. There used to be a special site where you could purchase ADP 1/2 or Nexus One when you registered for an Android Market account as a developer. Not any more. Google now expects you to purchase ANY Android device out there (including their Nexus) for development and such. They also want you to mainly rely on AVD for development. A small tidbit here, you can unlock the bootloader on Nexus One, but that voids warranty!
Nexus S: This is the phone where it really started shifting focus to consumers and making the phone available for specific providers rather than just as an unlocked GSM phone.
Galaxy Nexus: This is really the device from where they want to make the Nexus line absolutely consumer driver, rather than developer driven. Hence the launching of the Play Store Devices section which only lists Galaxy Nexus and not Nexus S.
The main point at discussion here is that as a Nexus owner to whom initially the aura of Nexus device getting direct updates from Google was a selling point (which it does but after VZW intervention) is extremely disappointed by how has handled updates and it's communication. For me my Galaxy Nexus is a perfect development device since I don't need/want to put anything other than Google factory image on it. The point here again is that Google at IO2012 and on Google+ has announced Jelly Bean for ALL Galaxy Nexii, not just the GSM version, so why does it take such silence and then few extra months for me to get it on my Verizon device?
