Debian is a popular Linux distribution, which is used primarily on personal computers, but numerous people have begun using it lately as a web server OS too, due to the stability and protection it provides. The latter is a consequence of the fact that Debian is developed and supported by a large number of qualified volunteers around the globe, so that any patch which is necessary to fix some issue is released in a couple of days. The same community will also help you with any question or trouble which a user may ever encounter, due to the fact that they can be contacted via e-mail using e-mail lists and a qualified response will be sent in no more than 15-20 min. The advantage here is that all of 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 kind of license fees to use it and you can personalize it as much as you want or need. This is valid for the Operating System as well as the 30.000+ software packages which are readily available for it.