Debian is an Operating System that uses the Linux kernel. Although it is usually installed on desktop computers, 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 need to be restarted for months. Debian is also regarded as being one of the most safe Operating Systems nowadays, due to the fact that security patches are released within days after a problem is discovered. This is possible since thousands of skilled developers are employed by the Debian project on a voluntary basis and not only do they work on the OS itself, but they also provide 24/7 support via special e-mail lists and respond within 20 min to any question. In this light, 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 one of several Linux releases with the highest number of packages - more than 30,000. Since the Operating System costs nothing to use, you will be able to modify both the core as well as any of the packages in the way you see fit. Also, you will not need to pay any license fees.