Debian is a widespread Linux release, that's used mainly on personal computers, still numerous people have started using it lately as a web server Operating System as well, because of the stability and security it supplies. The latter is a consequence of the fact that Debian is developed and supported by thousands of qualified volunteers around the globe, so that any patch which is necessary to fix a particular issue is released in a matter of days. The very same community can also help you with any question or issue which a user may ever experience, because they can be contacted via email using e-mail lists and a qualified response will be sent in around 15-20 min. The advantage here is that all of your questions will be responded to by the same people who have created the Operating System itself and they have an in-depth knowledge of how it works. As Debian is free, you won't need to pay any kind of license fees to use it and you'll be able to customize it as much as you want or need. This is valid for the Operating System and the 30.000+ software packages which are available for it.