Open-source software advocacy is when people work to get more people to use and develop open-source software. Open-source software is software that anyone can use, modify, or share for free. People who do open-source software advocacy help spread the word about how great open-source software is and how it can be used in lots of different ways. They also help people learn how to use the software and how to develop it further. This helps create an active community of users and developers who share with each other and continue to make the software better.