A Brief Explanation of Open Source
In the early 1980s MIT programmer Richard Stallman decided to build a replacement to the very expensive, proprietary UNIX computer operating system and make it completely free. His idea of what free meant extended the boundaries a bit when he formed the Free Software Foundation (FSF) and included in his mission statement, "availability of source code and freedom to redistribute and modify software are fundamental rights." Out of this the General Public License (GPL) was born.
Whereas proprietary licenses like those that are necessary when running a Windows machine ensure that we never actually own the software but are only licensed to use it, licenses such as the GPL ensure that we own every bit of the software we need to use. More prominently, we own the source code (the set of instructions which creates a piece of software) and are free to change that code if needed. Even more astoundingly, we may redistribute that software as long as we do so in the same fashion in which we received it, e.g., freely.
This type of license has been called a "viral license" since everything derived from the software must legally remain free. While that description was intended to be derisive, it does accurately describe the free nature of the GPL license and the code it protects. There are hundreds of different licenses deemed free or open source compatible, and all address different areas of protection. Some are even a couple of lines simply stating that you may do with it what you wish.
Benefits of Open Source
So where does this fit in with our work? If we simply look at the cost of owning a copy of Windows and translate that to some of the people we work with, the benefits are quite obvious. A single license for using Windows on a machine is US$200-300+ depending on which version. That's a cost on top of the hardware costs, though often it is included in the total price. A copy of Ubuntu Linux, for example, is free. Giving that copy of Ubuntu to your mother after you have installed it is also free and legal. When it is time to upgrade to a new version, the Windows machine will cost around US$100; that Ubuntu machine will once again be free.
Still, there are many other benefits that might not be apparent to those who aren't familiar. The free/open source software community is unlike any other in the world. People from all over the world contribute to the creation of a wide variety of software. The communities all determine various ways to organize and maintain their projects, but what they all have in common is that since everyone has the right to see and change the code, many people submit those changes back to the project to make it better and stronger. These applications develop on a very rapid pace, but they are also highly peer-reviewed. This can often translate to very stable applications with fewer security risks.
This is, simply put, freedom and access to tools that allow people all over the world to make their lives and the lives of others easier.