Debian is an OS that uses the Linux kernel. Though it is usually installed on desktop computers, it's being used on more and more web servers as well. The reason is that it is really stable, so a server running it will not have to be restarted for months. Debian is also regarded as being one of the most risk-free Operating Systems out there, as security patches are released within days after a problem is discovered. This is possible since thousands of experienced developers are part of the Debian project on a voluntary basis and not only do they work on the OS itself, in addition, they provide 24/7 support via special mailing lists and respond within twenty minutes to any question. In this light, you'll have top-level support directly from the developers who know their own platform in depth, and not from a third-party support team. Debian is also among the Linux distributions with the highest number of packages - over 30,000. As the Operating System costs nothing to use, you will be able to modify both the core as well as all of the packages in any way you see fit. In addition, you won't need to pay any kind of license fees.