Ubuntu is a widespread desktop OS, that uses the Linux kernel, but its server release is getting pretty popular too. The main reason is the fact that the OS is really light and it'll run on almost any kind of hardware with no issues, utilizing its resources to the max. Ubuntu is also extremely reliable and secure and all Long-Term Support (LTS) releases are supported for a minimum of 5 years, which guarantees that you should have a secure and stable software environment on your server all the time. In addition, Ubuntu has one of the biggest user communities on the planet, which means that if you experience any issue or have any question, you'll find plenty of resources on the net. Among the basic advantages of this OS is that it features thousands of software packages that can be easily customized in accordance with your needs as well as the requirements of the applications that you want to run, not to mention that you will not have to pay any kind of license fees at any time. In comparison, other OS's are paid and their code isn't accessible, which means that it cannot be changed.