The Solaris servers I am on all day at my job (when I'm not procrastinating on HN, that is).

Last time I installed Arch, it did not. Also checking Scientific, it does not (assume also RHEL/CentOS).

Arch definitely doesn't. sometimes I accidentally type vi and am confused for a few seconds why things dont work right. Luckily an alias will fix it.

Is it a case where vi is a version with the tiny feature set and vim has a larger (huge) feature set?

No. It was like that (where vi is just a lightweight recompile of vim) several years ago. Since then Arch has switched to using ex-vi[1], the closest thing to 'authentic' vi you can get nowadays.

[1] http://ex-vi.sourceforge.net

Sounds reasonable. I was about to guess a similar thing. A minimal Debian install (perhaps Ubuntu and other child-distros as well?) installs a vim-tiny[1], which often throws people off[2].

[1] http://packages.debian.org/squeeze/vim-tiny

[2] http://www.google.com/search?client=safari&rls=en&q=...

But Debian, etc. updates /usr/bin/vi to point to the Vim with the most features.

The last time I used AIX (I believe it was 5.3), it had old-school vi on it. I would bet this is true of newer revisions of AIX, as well as other commercial UNIX(tm) systems. I would also not be surprised to learn that some/most of the BSD systems still use it.

I don't think any of the free BSDs distribute the classic vi by default anymore, but they've standardized on nvi rather than vim as their "enhanced vi" of choice.

FreeBSD. Although it is mapped to nvi instead, ever since 4.4BSD.