Debian is a Linux release, that's widely used for desktop machines, yet it has been gaining popularity as a server Operating System over the last couple of years as well. It is very dependable and secure, because fixes are released within a couple of days after a problem is discovered. Debian has a vast support community, so when you have any kind of questions or troubles with the OS or with any of the 30,000+ packages it includes, you'll be able to contact the developers directly through electronic mail using special mailing lists and receive a response in 15-20 minutes. The Debian community supplies the top level of support possible, since all your questions will be handled by the very same people that made Debian in the first place, so they have a thorough knowledge of how their system works. As the Operating System is 100% free to use and distribute, no license charges will be added to your web hosting fees and you can modify the code files and any other software which you install without any restrictions, to optimize the software environment for your web sites. Furthermore, Debian performs very well on any hardware, as it's light and fast and doesn't require much memory.