Debian is a Linux release, which is widespread for desktop computers, yet it's been gaining popularity as a server Operating System over the last few years too. It's very dependable and safe, as fixes are released in a couple of days after a problem is discovered. Debian has a vast support community, so when you have any questions or issues with the OS or with some of the 30,000+ packages it includes, you can easily contact the developers immediately through email using special e-mail lists and receive a response in 15-20 minutes. The Debian community supplies the top level of support possible, since all of your questions will be handled by exactly the same people that built Debian in the first place, so they have an exhaustive knowledge of how their own system functions. As the Operating System is absolutely free to use and distribute, no license costs will be added to your web hosting fees and you can modify the code files and any additional software which you install with no restrictions, so as to optimize the software environment for your sites. Furthermore, Debian performs really well on any hardware, as it is light and efficient and doesn't need much memory.