In no particular order, let's take a quick look at some free/open source software that you are very likely to use (even if indirectly) every single day, and you don't even realise exists.
Of course, if you're a geek (or just have some knowledge of this kind of stuff), you might know about some, or all, of these applications, but still, it's easy to take some of these gems for granted. So, here's some recognition for five of those unsung heroes.
1 - OpenSSL
OpenSSL is a free toolkit which powers the encryption in many different applications on the internet. It's what keeps your credit card details safe when buying online and your passwords are properly secured.
Both servers and browsers, IM applications, or basically anything that uses the internet in a secure manner, probably uses OpenSSL.
That includes Firefox, Opera, Safari, Apache (with mod_ssl to be completely accurate) and many many more!
There are also non-free implementations of the SSL standard, like those found in Internet Explorer (everyone's favourite love-to-hate browser) and some other server setups too, but among the others, OpenSSL is ubiquitous.
2 - Samba
Samba is an open source implementation of Windows' file sharing system.
It provides the ability to share files with Windows machines on basically all kinds of devices - non-Windows servers, non-Windows desktops, Network Attached Storage devices, other embedded devices with file sharing capabilities - Samba has an insane number of uses. Take a look at this list.
If at any point you are sharing files between machines running Windows and devices that aren't, you probably have Samba to thank.
3 - GCC
GCC is the GNU Compiler Collection. As the name suggests, it's a collection of compilers (a compiler being a program that turns source code into an executable program) that are used very extensively.
In the old days, you might have had to pay thousands of dollars to get your hands on a compiler to turn your carefully-crafted source code into something you could actually run on a machine. Well, you still can end up paying lots, but GCC was one of the first free and Free compilers and certainly is one of the most important compiler colections in the industry right now.
Next time you launch Firefox (on any platform), or virtually any Linux/Unix app, remember that GCC got that application from source to the state where you can run it.
4 - Apache HTTP Server
If you deal with website building or administration at all, you probably do realise you use this, but the average web user probably doesn't.
Apache is the web server software that powers over 60% of websites. So roughly 60% of the time you browse to a site, your computer will be talking to an Apache server to get that web page you want.
5 - The GNU tools
While not everyone uses these every day, it's easy to forget how important Stallman and friends' software is. The aim of the GNU project was to make a completely Free operating system, and so there are shedloads of GNU projects that have made their way here, there and everywhere.
Without getting into the endless (and pointless) GNU/Linux vs. Linux argument, the GNU tools are a vital foundation to whatever you want to call the fusion of the Linux kernel and the GNU tools.
Without them, we wouldn't have a GPL licensed shell, basic command line utilities and a host of other graphical and non-graphical apps (GCC being one of them, but it deserved it's own entry!).
And now it's your turn...
So what unsung heroes in the free software/open source world do you think deserve a mention? Let us know in the comments below!