Debian is an OS that uses the Linux kernel. Although it is usually set up on desktops, it's being used on an increasing number of web servers as well. The reason is that it is very stable, so a server running it will not need to be restarted for months. Debian is also regarded as being one of the most protected Operating Systems to be found, as security patches are released within days after an issue is found. This is possible because thousands of well-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 in 20 minutes to any question. Thus, you'll obtain an outstanding level of support directly from the developers who know their own platform in detail, and not from a third-party support team. Debian is also one of several Linux distributions with the highest number of packages - over 30,000. As the Operating System is free to use, you are able to modify both the core and any of the packages in the way you see fit. In addition, you won't need to pay any kind of license fees.