When people talk about lowercase-f "free", they often aren't talking about copyleft- in my experience lowercase-f "free" is ambiguous to a lot of people. People

When people talk about lowercase-f "free", they often aren't talking about copyleft- in my experience lowercase-f "free" is ambiguous to a lot of people. People who know nothing about open source software might assume free-as-in-price. Even people who know quite a bit about open source licensing might use lowercase-f "free" to refer to open source licenses in general, despite RMS and the FSF attempting to own that word in Orwellian fashion. That's a long way of saying, I disagree with your definition of copyleft as simply requiring you to keep your modifications free- rather, the definition of copyleft simply requires you to keep your modifications also copylefted. I'm sure you know that as well, I'm not nitpicking you so much as using your comment as a starting point for a tangential rant. :) Of course, if you buy into the FSF's attempt to co-opt the word "free" to only refer to their brand of freedom, what you said makes sense, but their habit of trying to co-opt common, ambiguous words like "freedom" to mean something very, very, very specific that they define is probably one of the top 2-3 reasons why they've driven so many people away from their cause over the past few decades. If they mean copyleft, they should just say copyleft. Trying to co-opt "free" is at best either dishonest marketing (because who hates freedom, right?) or a dishonest rhetorical device. It's used as a passive aggressive way of laying claim to a word that means lots of different things to lots of different people, even within the context of open source licensing. To the FSF's detriment, it confuses every single discussion about their goals, because it's never clear whether someone means free-as-in-beer vs. free-as-in-freedom vs. free-as-in-RMS. And let's be clear- free-as-in-freedom is a different thing from free-as-in-RMS. Free-as-in-RMS can be a great thing too, I just wish they would be more intellectually honest about it.