Thanks to everyone who commented on The Dubious Benefits of Porting F/OSS to Windows. There are a lot of good points in the comments.
For example, Simon Hibbs responded that more users of a piece of software increased the value of that software. This is important for programs that follow open standards, such as Mozilla Firefox, or OpenOffice.org and Abiword. In one sense, I see the value of open standards and unfettered access to data as more important than the four software freedoms. If I had to choose one over the other, I’d choose open standards… but I think that’s a false dilemma.
Yet I still wonder. How many people have switched to free platforms after realizing that they already used or could switch to completely free software that did what they needed?
I’ve seen plenty of people switch from a free OS to a proprietary system which includes some free parts (let’s call it “Mac Something Something”… or how about “Something OS X” to protect the innocent), justifying that choice by saying “It can run all of the applications I love from Linux or *BSD, and look it’s shiny!”
I’m not sure that that case really helps the goal of spreading free software.
Again, I realize that not everyone shares that goal with me, and it’s fine. I’m also not saying that porting free software to proprietary platforms is bad, or wrong, or makes you an evil person. I’m sympathetic to the idea that plenty of people develop on non-free platforms and deploy to free platforms. In my last full-time development job, I would have gone crazy if not for Cygwin. (I ended up using its X server to connect to our GNU/Linux test machine just so I could use decent development tools.)
Yet still I wonder… is there concrete evidence that people do switch to free platforms after using primarily free software? Is there concrete evidence that open standards gain significant acceptance due to the presence of free software or software that otherwise promotes those standards effectively? (I’d like more than one case; it’s possible that Mozilla is an outlier.)
(I haven’t brought up the case of writing free software that supports only a proprietary standard, but that’s a different post altogether.)