Software licence
Another type of software licence is an open source distribution licence. These licences let software developers choose what people can and cannot do with the code of the software. There are many licences freely available which allow you to do this, such as the MIT Licence, which allows for the software to be used by any person for any reason/purpose. The GNU General Public Licence, often abbreviated/shortened as GPL is a licence which makes all copies of the software free and open source. Therefore, GPL cannot be included in any part of proprietary/closed software because it does not follow the rules of the licence. The Apache Licence is more definitive and specific, but is more common with larger companies, such as Google, but is still considered a free software licence. Creative Commons is a popular licence used by people who want to give something out for free without taking as much credit. Creative Commons is very open, and is even used by Wikipedia for its pages and other content.