Debian is a popular Linux distribution, which is used mainly on desktop computers, however lots of people have begun using it lately as a web server OS too, due to the stability and security it supplies. The latter is a consequence of the fact that Debian is developed and supported by countless qualified volunteers worldwide, so that any patch that is needed to fix a particular issue is released within a couple of days. The very same community can also help with any question or issue that a user may ever have, since they can be contacted via e-mail using mailing lists and a qualified response will be sent in no more than 15-20 minutes. The advantage here is that all your queries will be responded to by the same people who have made the Operating System itself and they have an in-depth knowledge of how it works. As Debian is provided for free, you won't have to pay any kind of license fees to use it and you will be able to personalize it as much as you want or need. This is valid for the Operating System and the 30.000+ software packages that are available for it.