Free software is a funny thing, partly because it tends to spark off “holy wars”, so it can be hard to focus on the practical issues when you’ve got people shouting about their vision of purity. I like this blog post (a parody), which applies those principles to cars: The transmission tax.
Most of the people reading this are probably aware of the basic principles, but here’s a quick recap. If you get a piece of software for your computer, it can be “closed source” or “open source”. Closed source is something like Microsoft Office or Adobe Reader: you get the application itself, so you can run it on your machine, but you don’t get the source code that the programmers used to create it. Open source means that you get the source code too, and there are some (theoretical) advantages to this: