The open-source movement is a collaborative initiative that promotes the free distribution and modification of software. It encourages developers to share their source code, allowing others to study, improve, and adapt the software for various uses. This approach fosters innovation and community engagement, as anyone can contribute to projects, leading to more robust and versatile applications. Key examples of the open-source movement include projects like Linux, an operating system that powers many servers and devices, and Apache, a widely used web server software. These projects demonstrate how collective efforts can produce high-quality software that benefits users and developers alike, often at no cost.