Debian is a Linux distribution, which is widespread for desktop machines, however it's been becoming more popular as a server OS during the last few years too. It is very stable and secure, because fixes are released in just a couple of days after a problem is discovered. Debian has a large support community, so if you have any questions or problems with the OS or with some of the 30,000+ packages it features, you can contact the developers without delay via email using special mailing lists and receive a reply in just 15-20 min. The Debian community provides the best level of support possible, because all your questions will be handled by the very same people that created Debian in the first place, so they have a thorough knowledge of how their own system operates. Since the Operating System is 100% free to use and distribute, no license charges will be included with your hosting fees and you'll be able to customize the code files and any other software which you install without restrictions, in order to optimize the software environment for your websites. In addition, Debian performs really well on any hardware, as it's light and effective and does not need a lot of memory.