Debian is an Operating System which uses the Linux kernel. Though it is usually installed on desktop computers, it's being used on a growing 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 experienced developers are working for the Debian project on a voluntary basis and not only do they work on the OS itself, they also provide 24/7 support by using special e-mail lists and respond in twenty 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 depth, and not from a third-party support team. Debian is also among the Linux distributions with the highest number of packages - more than 30,000. As the Operating System is free to use, you're able to modify both the core as well as any of the packages in any way you see fit. Furthermore, you won't have to pay any kind of license fees.