A long-standing challenge for advocates of Free and Open Source Software (a.k.a. FOSS) has been explaining just what the term Free Software means, because in English,* the word “free” has several unrelated meanings. The classic explanation has been to compare “free speech” and “free beer.”
You see, when the average person hears the phrase “free software,” they generally assume it means the same kind of thing as “free beer.” But it’s really about the software being unencumbered – it’s about your ability to use, study, learn from, and improve the software. It’s not about the price tag.
The problem with the “free speech” label is that the phrase has its own very specific meaning and political overtones. As a result, people tend to focus on the ideas inherent in freedom of speech, dealing with software as a form of expression and focusing on issues like censorship. These are valid issues, but not the heart of what “free software” means.
Today I read a post on Groklaw describing it in terms of “free as in coffee” vs. “free as in liberty” – primarily because he didn’t like the association with beer – but I liked the use of liberty (edit: or just freedom if you want to keep the phrasing consistent) rather than speech, because it conveys the meaning without bringing in other issues.
(Ironically, the FSF page explaining the phrase links to a list of confusing words and phrases that are worth avoiding… that doesn’t include “free!” Update: These days it lists “for free,” “freely available” and “freeware”…but that still doesn’t solve the confusion of “free.”)
*In other languages, the meanings are more distinct. There’s no confusion between software libre and software gratis.