Debian is a Linux release, that's widespread for desktop machines, but it's been becoming more popular as a server Operating System over the last few years too. It's really dependable and risk-free, since fixes are released within a couple of days after a problem is discovered. Debian has a huge support community, so when you have any kind of questions or problems with the OS or with any of the 30,000+ packages it includes, you can contact the developers straight away through electronic mail using special e-mail lists and receive a response in 15-20 minutes. The Debian community offers the top level of support possible, as all your questions will be handled by the very same people that built Debian in the first place, so they have a thorough knowledge of how their system operates. Because the Operating System is 100% free to use and distribute, no license costs will be added to your web hosting fees and you'll be able to customize the code files and any additional software which you install with no restrictions, in order to optimize the software environment for your websites. In addition, Debian performs really well on any hardware, because it's light and efficient and does not require much memory.