> The Linux ecosystem has many Linux distributions based on the Linux kernel.
There are many operating system distributions that run the Linux kernel. But something like Debian/kFreebsd or illumos are in many ways quite similar to other distributions like Ubuntu -- without running on Linux.
The Linux kernel is a tremendously important piece of the Free software world we live in -- but it isn't a userland -- and I don't understand why people that actually understand the difference gets so worked up about it.
The GNU userland is important. The Gnome project is important. Xorg is important. The Apache foundation software is important. I don't see why people insist on labelling these things "Linux".
The GNU name actually makes sense: GNU's not unix. But it's close. You can compile GNU software and run it on Microsoft Windows. Or under OS X. GNU is a platform. Sort of.