Debian is an OS which uses the Linux kernel. Though it is usually set up on personal computers, it's being used on an increasing number of web servers too. The reason is that it is really stable, so a server running it will not have to be restarted for months. Debian is also considered to be among the most safe Operating Systems available, because security patches are released within days after an issue is found. This is possible because thousands of experienced developers work 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 e-mail lists and respond in 20 minutes to any kind of question. Thus, you'll enjoy 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. Since the Operating System is free to use, you can modify both the core and all of the packages in any way you see fit. In addition, you will not be required to pay any license fees.