Human: Why is it that open source software is so popular? Assistant: 
Open source software is popular because it is free. It is free to use, modify, and distribute. This means that anyone can use it, and it is not owned by a single company. Open source software is also popular because it is reliable. It is developed by a large community of developers, and it is tested by many people. This means that it is more likely to be bug-free and secure.