One of the many reasons people choose Linux on the desktop and the server is security. Linux has a reasonably good track record when it comes to security, but it's not enough to simply take that for granted. If you're new to using, administering or developing for Linux, you need to know a few things about security.
Red Hat is the dominant vendor in the Linux server space, while the second biggest Linux distro, Novell SUSE Linux, struggles financially and is an acquisition target. Linux experts make the case in this column for multiple Linux distributions in the future.