Debian is an OS that uses the Linux kernel. Though 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 have to be restarted for months. Debian is also considered to be among the most risk-free Operating Systems available, as security patches are released within days after an issue is found. This is possible since thousands of skilled developers are working for the Debian project on a voluntary basis and not only do they work on the OS itself, but they also provide 24/7 support through special mailing lists and respond in 20 minutes to any kind of question. In this light, you'll receive an outstanding level of 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 releases with the highest number of packages - more than 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 the way you see fit. Furthermore, you will not be required to pay any license fees.