Earlier this month, the FCC explained why they use and contribute back to open source software:
Here at the FCC, we’re always excited when we can contribute to open source software. Open source software is just like any other software, except the creator publishes the underlying source code that powers the application, allowing others to improve upon or adapt the project to their own needs, and hopefully, contribute those improvements back to the community to do the same. Think of it as the software equivalent of the “give a penny, take a penny” jar at your local convenience store.
The FCC contributed back to the WordPress community in the form of a faceted search widget available in the WordPress.org plugin repository and we hope they’ll continue to contribute more code back in the future.
It’s worth a read and sending to anyone you know using WordPress who could contribute something back to the community via code, support, documentation or more.