You’ve read the GPL’s preamble, you can name the Four Freedoms, and you do your best to keep proprietary bits off our computers. But what’s the future of free software in the era of Flickr, Google Apps, and Facebook?

What it means to be free

The term free software was defined by Richard Stallman. We know Stallman as the founder of the GNU Project, the author of the General Public License, and founder of the Free Software Foundation. Stallman defined free software this way: not by the price of the software, but by the freedoms it accords to its users.

Specifically, users of free software are free to:

> Use the software for any purpose
> Study how the program works
> Change the software, modifying the source code to meet the user’s needs
> Redistribute the software, with or without modifications—to share the software.

Free software is also known as open source. Access to the source code of a program is a precondition of the aforementioned freedoms—specifically, the freedoms to study the program and to modify it.

So what are the characteristics of free software?