Debian is an Operating System that uses the Linux kernel. Even though it is usually set up on desktops, it's being used on more and more 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 risk-free Operating Systems to choose from, because security patches are released within days after an issue is found. This is possible because thousands of well-trained developers are working for the Debian project on a voluntary basis and not only do they work on the OS itself, in addition, they provide 24/7 support through special mailing lists and reply within 20 minutes to any question. Thus, you will enjoy top-level 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'll be able to modify both the core and all the packages in the way you see fit. Furthermore, you will not be required to pay any kind of license fees.