Debian is an Operating System which uses the Linux kernel. Though it is usually installed on personal computers, it is 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 need to be restarted for months. Debian is also considered to be 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 because thousands of well-experienced 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 via special e-mail lists and reply in twenty minutes to any question. In this light, 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 costs nothing to use, you're able to modify both the core as well as all of the packages in the way you see fit. Also, you will not need to pay any kind of license fees.