Debian is an Operating System which uses the Linux kernel. Even though it is usually installed on desktops, it's 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 regarded as being one of the most risk-free Operating Systems to be found, because security patches are released within days after a problem is found. This is possible since thousands of qualified 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 by using special e-mail lists and respond within 20 minutes to any kind of question. Thus, you'll 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 - more than 30,000. Since the Operating System is completely free to use, you can modify both the core and all the packages in any way you see fit. Also, you will not need to pay any license fees.