Debian is an OS which uses the Linux kernel. Although it is usually set up on desktops, it is being used on an increasing number of web servers as well. The reason is that it's very stable, so a server running it will not have to be restarted for months. Debian is also considered to be one of the most safe Operating Systems available, because security patches are released within days after a problem is discovered. This is possible because thousands of experienced developers are employed by 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 e-mail lists and reply within 20 minutes to any kind of question. Thus, you'll obtain 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 releases with the highest number of packages - more than 30,000. As the Operating System is free to use, you can modify both the core as well as any of the packages in any way you see fit. In addition, you won't have to pay any license fees.