Opinion: Why free beer trumps free speech

The spirit of open-source might once have been summed up as "share and share alike." This philosophy has its roots in the GNU General Public License (GPL), which is the license for the Linux kernel (the operating system engine) and most of the core operating system utilities that come with Linux.

The GPL is basically a reciprocal agreement. If you improve or add to a GPL program, or if you build an application that includes software licensed under the GPL, then you must make the source code for your application available, too. Share and share alike. That's not to say you can't sell GPL software; you can. Put simply, the Free Software Foundation promotes the concept of software that is free as in "free speech," not necessarily free as in "free beer." Free means open and unrestricted by pre-existing proprietary claims; it doesn't mean without cost.

According to the most recent Evans Data survey of Linux developers, however, people are more interested in free beer than they are in free speech.

Given human nature, that shouldn't be surprising, but it runs contrary to the original philosophy of open-source software.

For example, the developers surveyed have a clear preference for software built with the Qt tool kit over the competing tool kit, GTK.

They clearly see the superiority of software built with Qt over software built with GTK. But when asked which tool kit they use to build their own software, the majority chose GTK. While there are alternate explanations for some of this seeming contradiction, other data in the survey suggests this is all about money and licenses.

Here's the crux of the matter: It's illegal to create and sell a proprietary application based on GPL code. Given the reality that people are always going to create proprietary applications, developers invented some license compromises that make it possible to build proprietary applications on open-source foundations. These compromises usually fall into one of two categories I call "quid pro quo" licenses and "free beer" licenses.

Quid pro quo licenses are conditional licenses, often called dual licenses. These licenses have GPL-like conditions for those who want to write free, open-source software, but they require developers to pay a license fee to create for-profit proprietary applications. Qt has such a dual license. Those who use Qt to build proprietary, for-profit applications have to buy developer licenses from Trolltech, the inventors of Qt. But the people who used Qt to build KDE, KDevelop and all the other top-rated software didn't have to pay to use Qt, because KDE, KDevelop and so on are all open-source and free.

Free-beer licenses make it possible to incorporate open-source code into a proprietary for-profit application without any financial obligation.

The widget tool kit GTK is available under the Lesser GPL, meaning you use GTK to build open-source or proprietary applications with no obligation to publish your source code or financially compensate the authors of GTK.

Quid pro quo licenses are ethically consistent. Open-source developers can use the software for free, but they must contribute their work back into the open-source pool of software. Share and share alike the source code. Other developers can use the software for profit, but they must financially compensate the company whose hard work they're leveraging for profit. Share and share alike the profits.

Free-beer licenses, on the other hand, are ethically inconsistent. They enable companies to exploit the hard work of others for profit without giving anything back in the way of source code or money. At most, some of these licenses require developers to include a copyright or otherwise credit the original authors.

So why would anyone work on free-beer software if it amounts to volunteering to be exploited? No doubt the developers of free-beer software like GTK get some gratification from knowing their work is the most frequently chosen, even if the choice has little or nothing to do with the quality of their work. And nobody is compelling them to contribute free-beer software. That's yet another aspect of free: free will.