Debian is a Linux distribution, that is widely used for desktop computers, yet it has been gaining in popularity as a server Operating System during the last couple of years too. It is really stable and safe, since 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 includes, you can easily contact the developers straight away through email using special mailing lists and receive a response in just 15-20 min. The Debian community gives you the best level of support possible, since your questions will be handled by exactly the same people that created Debian in the first place, so they have an in-depth knowledge of how their system functions. Since the Operating System is absolutely free to use and distribute, no license costs will be included with your web hosting fees and you'll be able to change the program code files and any other software which you install with no restrictions, so as to optimize the software environment for your web sites. Furthermore, Debian performs very well on any hardware, because it's light and efficient and doesn't require a lot of memory.