"Ask someone familiar with computers to suggest where the
Microsoft Windows operating system will be in one year and, more
than likely, you will hear about Vista, the newest iteration, or
about enhancements to XP, the current version. Ask someone familiar
with the Linux operating system to answer that same question and
it's likely you will be asked which OS you mean.
"Linux, an open-source OS kernel developed by Linus Torvalds in
1991, currently claims 15 or more popular variations or
distributions, according to Linuxiso.org, a site that offers Linux
distributions for downloading..."