How two of the world's largest websites use Linux for high availability

Two examples of why linux is great - how Digg and Wikipedia serve so many pages with Linux on the back-end

http://www.itwire.com/content/view/21586/1141/1/0/

Highlights: 5 administrators are all it takes to administer the 400 servers that serve up wikipedia to 600+ million people per year.  Both Digg and Wikipedia now use debian-based distros - digg actually uses Debian, while Wikipedia opted for Ubuntu (after switching from Redhat not too long ago).  Also, both sites use MySQL as a backend database.

FYI, I'm not quite up to the 80 server/admin ratio of Wikipedia, but administer ~30 right now in just a couple of hours a week when I'm not running experiments or programming.  :o)