Debian is a widespread Linux distribution, which is used primarily on PC's, however a lot of people have begun using it lately as a web server OS too, due to the stability and security it offers. The latter is a result of the fact that Debian is developed and supported by countless qualified volunteers all around the world, so that any patch that is needed to fix some issue is released within a matter of days. The very same community can also help with any question or issue which a user may ever have, due to the fact that they can be contacted via email using e-mail lists and a competent response will be sent in around 15-20 minutes. The advantage here is that your queries will be responded to by the same people who have created the Operating System itself and they have a detailed knowledge of how it functions. As Debian is provided for free, you will not have to pay any license fees to use it and you can personalize it as much as you want or need. This is valid for both the Operating System and the 30.000+ software packages which are available for it.