Ubuntu is a widespread desktop OS, that uses the Linux kernel, and its server release is getting pretty popular too. The reason is that the OS is amazingly light and it can function on almost any hardware without any issues, utilizing its resources to the max. Ubuntu is also really reliable and secure and all of the Long-Term Support (LTS) versions are supported for a minimum of 5 years, which guarantees that you will have a secure and stable software environment on your server at all times. In addition, Ubuntu has one of the biggest user communities worldwide, so if you experience any problem or have any question, you will find plenty of resources on the net. Among the major advantages of this OS is the fact that it includes tens of thousands of software packages that can be freely changed in accordance with your needs and / or the needs of the apps which you'd like to run, not to mention that you won't have to pay any kind of license fees any time. In comparison, other Operating Systems are paid and their code is not accessible, which means that it can't be changed.