What are the benefits of participating in open source?
Depending on the project and your role in it, you might get lots of different benefits.
Learn new languages and tools to keep your skill set current.
Practice techniques that you might not be able to justify putting time into in a corporate environment. (For example, coding for extreme security or efficiency or minimum power and memory usage.)
Make connections with people outside your company.
Signal your technical competence and ability to work with others. Often, willingness to put time into open source depends on the job market for high-skill non-management programmers. The more that the hiring process depends on formal education and certification, and the less input it has from peers, the less incentive that a programmer has to Signal his or her skill using open source.
Talk with real users about bugs and features without a company filter, to get a better understanding of a software problem space.