These are the four freedoms that a program must legally provide in order for it to be considered Free Software. Often times, when trying to convince non-techies of the advantages of Free Software, these freedoms seem very abstract and, to be honest, useless to them. They may see the advantages of freedom 0, but freedoms 1-3 all seem to either be for programmers or something they would just never use, and don't need others to have the ability to use. However, those of us who are familiarized with Free Software know that even non-programmers can benefit greatly from using Free Software, or (what's the same) avoiding proprietary software. And for this, I like to use a little anecdote of when I first started to advocate for Free Software, when I wasn't even an avid programmer.
I believe I've mentioned this story twice now, but never in this context (usually always in my criticisms of Apple). The story goes that when I was 16 I had my own laptop which was a hand-me-down, my father's old work computer. It was a Dell Latitude - I can't remember specifically which model, but it had a port to connect to a dial-up modem. The laptop was rather old, so it couldn't run Windows, and so I began to use GNU/Linux. This was, at the time, a purely pragmatic choice, not a conviction. However, my family (aside from my father) generally used Apple products, so my music player was an Apple iPod. For a year I synced my music with the family macbook, until I decided to move my music to my own laptop so as to become fully independent of the family computer. So I migrated all my music to my laptop, installed Banshee (a program to manage music libraries, like iTunes), and synced my music to the iPod. Or so I thought. When Banshee told me the music had finished syncing I ejected and unplugged the iPod, scrolled through the music catalogue and found that... nothing had changed. As if it hadn't synced. I won't bother you with the details of my troubleshooting this problem, but eventually I found out that the filesystem that Apple uses on their iPods has a journaling feature enabled that was not supported by the drivers that Linux had at the time, but luckily I could turn off the journaling from a Mac computer. So I did that, came back, synced my music and it worked... for a time. Then, another day, the battery on my iPod was low so I turned it off. I came back home, charged it, turned it on. Then later I tried to sync some new music on to the iPod and, wouldn't you know it, the journaling system was back on. Every time the iPod got restarted the journaling system would be enabled. Which meant that every time the iPod got restarted I had to plug it back into the macbook in order to turn of the journaling.
At a first glance, many non-techies may assume that this is the fault of Linux for not fully supporting the filesystem. But it is in fact the fault of Apple, who did not wish to disclose documentation on how to write the drivers to interact with the filesystem. Where the filesystem used on the iPod documented, and the source for its usage available, any driver developer could have (and would have) been able to create a fully functional driver.
The injustice here is that despite having bought an iPod, I was not the real owner of that iPod. Apple was. I was simply renting it. For Apple was able to tell me what kind of software I can use their product with, despite it being my property. And this isn't something that affected me because I'm a programmer, but rather it's something that affects anyone who uses proprietary products. They tell you what to do with your property because it's beneficial for their business.
Since then, I aimed to eliminate all proprietary software from my life (with varying degrees of success). I always looked for the software which would grant me the most control over my system. I aimed to be the one true owner of my system in its entirety. And this can only be accomplished by using Free Software.