I am a big fan of open standards and open source in general. As a consequence, I get a lot of questions like “Why would anyone give away valuable software for free?”
Businesses and other organizations often prefer to have code developed, maintained, and improved in the open source community when it does not contain technology specific to their application domain, because it allows them to focus more development resources on their core business.
Individuals contribute for the technical challenge, to hone their technical skills, for the sense of community, as part of their graduate school programs, as a way around geographic isolation, to enhance their employment opportunities, and as advertisements for their consulting services. There are probably as many reasons as there are individuals. Some of the apparently individual contributions come from employees of support companies with contracts from businesses or other organizations who have an interest in seeing that a library is well-maintained.
While it isn’t very difficult to imagine why open source software works, it is much harder to explain why Wikipedia works as there are fewer incentives at play. Very few infact. But wikipedia still works and it serves as an excellent starting point for finding information about absolutely anything. Maybe it is the sense of giving back to the community that makes it work or maybe something else. I can’t put my finger on what makes it work. The following joke I think sums up the mystery of wikipedia perfectly
The problem with Wikipedia is that it never works in theory, it only works in practice!