How Open source projects are developed and how do they maintain quality?

As you probably know there are hundreds of thousands of open source projects. Some are huge, such as the Linux kernel with over 20 million lines of code, other are small, only a few tens of lines of code. Some are maintaine by thousands of people, others by only one person. Some of the developers are paid for their work on the Open Source projects, others, the majority do it as volunteers.

These are the main questions we are going to answer in this presentation.

Why do people write free and open source projects in their spare time?

Project types: