Debian is a Linux distribution, that is widely used for desktop machines, yet it's been gaining popularity as a server OS during the last couple of years too. It is very stable and secure, as fixes are released within a few days after an issue is discovered. Debian has a vast support community, so if you have any questions or issues with the OS or with some of the 30,000+ packages it is equipped with, you can easily contact the developers right away via e-mail using special e-mail lists and receive a reply in just 15-20 min. The Debian community provides the top level of support possible, since all of your questions will be handled by the same people that built Debian in the first place, so they have a thorough knowledge of how their system works. Because the Operating System is free to use and distribute, no license costs will be included with your website hosting fees and you will be able to customize the program code files and any additional software that you install without any restrictions, to optimize the software environment for your web sites. Furthermore, Debian performs really well on any hardware, as it's light and effective and doesn't require a lot of memory.