Debian is one of the most popular Linux distros available, and is very often used in enterprise environments where reliability is key. It's interesting, then, to see that the Debian dev team decided to start including virtualization software as a standard package with their releases. Virtualization has been an immense buzzword lately, with just about everyone from Intel to AMD to Microsoft to HP to IBM supporting it. Of course, everyone has their own way of accomplishing it. Luckily for those embedded with Debian, their method is free and relies on OpenVZ, a server virtualization suite. OpenVZ is offered both free and as a commercial package from a 3rd party, and is rival to the other large popular free suite, Xen. Dana Gardner of Virtuozzo, the commercially sold adaption of OpenVZ, had this to say about Xen:

Referring to Xen virtualization software, which recently won inclusion in Suse Enterprise Linux 10 and will be part of Red Hat's (Nasdaq: RHAT) next major Linux release, Gardner said it is good to have more than one open source virtualization solution, adding the market will reward the most productive approaches.
Debian's adoption of OpenVZ also resulted in some changes in the way OpenVZ releases their code, and this was for the better. They switched the licensing for some of their tools from QPL to GPL, which offers more rights to the person using the software. OpenVZ's future goal is to be included as part of the Linux kernel.