Excuse my ignorance of not reading trough 6 pages of highly interesting but rather nitpickingy/ academic about what to call "linux".
I use personally about 5 different OS's on weekly bases ranging from Linux distro's (redhat, ubuntu, SLES...which I count as one) to AIX, Windows (in all its forms) , Solaris, HP-UX and even the odd OS/2.
If I use the word "Linux" then most tech people know it a distro using Linux kernel with GNU/etc software around.
John Do however almost has no idea bout the difference between Office applications a Browser or an OS.
They just "see" stuff on their screen what does stuff. They are not interested in what does what, they just want to do that.
Do Stuff.
The tendency on being over "religious" is one of the biggest reasons IMHO why it took so long to get "Linux" (or whatever you want to call it) on the desktop. PC's are for most people already confusing as hell. They know "MP3" means music in "pc terms" - no point in trying to dragg them to ogg if that stuff is not working on their "MP3" player. If they can't open "MP3" they are not happy, for them it means "no music".
Reason why I less and less talk about "Linux" to non-tech people but simply say "Ubuntu" - not because it's technically the best (what is?), but because that tend to work nice for John Do - it allows them to do "stuff" without worrying about what is actually doing it.
Having "one name" - just like microsoft "windows" managed to put in the "market" is all they care about to
describe a system that does something.
Even my parents are now saying to their friends that since they use that "Ubuntu windows" they have less "problems" and it's free, which makes it even better ... Open Office is for them just a part of that "Ubuntu stuff".
I know a friend of my parents who went to a big shop and was not happy because he wanted a laptop with that "new windows ubuntu version" and was utterly frustrated they did not sell those
.
Some with browers, if you show John Do that if he installs that "firefox" thingy and adds "adblock plus" websites load faster and the interface is not to different then they are very happy to stop clicking on that blue icon but on the curly foxy thing because there is a clear advantage.
This is a very successfully way of advocating "better" software, but you need a consistent (even if not 100% correct by some people opinions) name.