Debian is an Operating System which uses the Linux kernel. Although it is usually set up on personal computers, it is being used on a growing number of web servers too. 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 safe Operating Systems nowadays, as security patches are released within days after a problem is found. This is possible because thousands of well-trained 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 through special e-mail lists and reply within 20 min to any question. In this light, you will enjoy 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 - over 30,000. As the Operating System costs nothing to use, you will be able to modify both the core and all of the packages in any way you see fit. In addition, you will not be required to pay any license fees.