Debian is an OS which uses the Linux kernel. Although it is usually installed on desktops, it's being used on a growing number of web servers as well. The reason is that it is very stable, so a server running it won't need to be restarted for months. Debian is also considered to be one of the most protected Operating Systems to be found, due to the fact that security patches are released within days after an issue is found. This is possible because thousands of skilled developers are employed by the Debian project on a voluntary basis and not only do they work on the OS itself, but they also provide 24/7 support via special e-mail lists and respond within 20 minutes to any question. In this light, you will get 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 releases 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 all of the packages in the way you see fit. In addition, you won't need to pay any kind of license fees.