There are a number of distributions based on Debian. Some people might want to take a look at these distributions in addition to the official Debian releases.
A Debian derivative is a distribution that is based on the work done in Debian but has its own identity, goals and audience and is created by an entity that is independent from Debian. Derivatives modify Debian to achieve the goals they set for themselves.
Debian welcomes and encourages organisations that want to develop new distributions based on Debian. In the spirit of Debian's social contract, we hope derivatives will contribute their work to Debian and upstream projects, so that everyone can benefit from their improvements.
Why derive from Debian?
It can be faster to modify an existing distribution like Debian than starting from scratch since a packaging format, repositories, base packages and other things are specified and usable. A lot of software is packaged so there is no need to spend time packaging most things. This allows derivatives to focus on the needs of a specific audience.
Debian ensures that what we distribute is free for derivatives to modify and redistribute to their audience. We do this by checking the licenses of software we distribute against the Debian Free Software Guidelines (DFSG).
Debian has a number of different release cycles available for derivatives to base their distribution on. This allows derivatives to try experimental software, move really fast, update often with quality assurance, have a solid base for their work, use newer software on top of a solid base, enjoy security support and or extend that support.
Debian supports a number of different architectures and contributors are working on methods of automatically creating new ones for new processor types. This allows derivatives to use the hardware of their choice or to support new processor designs.
The Debian community and people from existing derivatives are available and willing to help guide new distributions in their work.
Derivatives are created for a number of reasons, such as translation to new languages, specific hardware support, different installation mechanisms or supporting a particular community or group of people.
How to derive from Debian?
Derivatives can use parts of Debian's infrastructure if needed (like repositories). Derivatives should change references to Debian (like the logo, name, etc.) and to Debian services (like the website and BTS).
If the goal is to define a set of packages to install, creating a Debian blend could be an interesting way to do that within Debian.
Why is Debian interested in derivatives?
Derivatives bring Debian to a larger number of people with more diverse experiences and requirements than the audience we currently reach. By developing relationships with derivatives, integrating information about them into Debian infrastructure and merging changes they have made back into Debian, we share our experience with our derivatives, expand our understanding of our derivatives and their audiences, potentially expand the Debian community, improve Debian for our existing audience and make Debian suitable for a more diverse audience.
Why use a derivative instead of Debian?
If you have a specific need which is better served by a derivative, you might prefer using it instead of Debian.
If you are part of a specific community or group of people and there is derivative that is for that group of people, you might prefer using it instead of Debian.