There are companies that defend their software, making it a competitive business resource, to be kept as confidential as possible. Others instead share it with the rest of the world, often to spread successful ideas and to improve everyone’s work. The latter case is that of open source software.
This approach to software development means that anyone can access, edit and share the source code of a particular technology. The source code is not usually accessible because it is a strategic resource to be protected, the real beating heart of the products and services belonging to companies and privates. Offering the source code to the world implies making the same technology available to everyone, which can be used freely to develop many other interesting products that can open new business horizons.
Whatever technology an open source project may be focused on, it will usually have a community of supporters who contribute to the spread and improvement of the technology. All around, companies and privates can develop independent business projects based on these technological resources, compensating the source project with monetary donations or contributing in turn to improvements.