Ubuntu is a preferred desktop OS, that uses the Linux kernel, but its server version is getting pretty popular too. The main reason is that the OS is extremely light and it'll run on almost any hardware with no issues, utilizing its resources to the fullest. Ubuntu is also extremely reliable and secure and all Long-Term Support (LTS) releases are supported for at least 5 years, which warrants that you should have a safe and stable software environment on your hosting server at all times. Also, Ubuntu has one of the largest user communities worldwide, so if you experience any difficulty or have any kind of question, you'll find lots of resources on the net. One of the key benefits of this OS is the fact that it features thousands of software packages that can be easily modified in accordance with your needs and the requirements of the apps that you'd like to run, not to mention that you won't have to pay any license fees at all. In comparison, other Operating Systems are paid and their code isn't accessible, thus it can't be changed.