Ubuntu is a Linux version derived from Debian. For questions about Ubuntu that are not about security, please post on [AskUbuntu.SE].
Ubuntu is a Linux version, derived from Debian. Ubuntu is licensed under the GPL, but it's development is in the hands of Canonical, Ltd, in the UK.
Use this tag for questions about security aspects of Ubuntu.
If your question is about another aspect of Ubuntu, you can ask it on Ask Ubuntu.
If your question is about Unix or Linux in general, and not about a security aspect of Unix or Linux, you can ask it in Unix & Linux.
The official site of Ubuntu is http://www.ubuntu.com .