Is GPL licensing in decline?

A debate has raged for months about open source licensing trends. It all started with assertions that the GNU General Public License (GPL) is rapidly falling from favor as an open source license, replaced largely by the Apache License. Free software advocates couldn’t disagree more.

What’s really going on? To understand the answer, you need to know a little background.

A capsule history of open source licensing The GPL is by far the most widely used copyright license. It’s intended to deliver the “four freedoms,” where end-users are free to use, study, modify, and distribute GPL-licensed software for any purpose. It’s associated with the “free software” movement, started by Richard M. Stallman in the early ’80s and now embodied in the Free Software Foundation (FSF).

The first version of the GPL was written by Stallman in 1989, and it’s since been updated twice, most recently to add protections against software patents. It’s notable for the controversial way it is crafted to achieve Stallman’s goal of creating an ever-growing pool of GPL-licensed free software by requiring that any other programs combined with GPL titles also have its copyright licensed under the GPL. This “copyleft” approach is the essence of the GPL’s controversial nature; some people consider it wrong to make access to the software conditional on allowing others the same access.

Significantly, the GPL is used to license the Linux kernel and is credited with creating a uniform licensing environment in which software from many sources — including Stallman’s own GNU Project — could be combined to create a working operating system. As the resulting “GNU/Linux” operating system rose to prominence, a great deal of software became available under the GPL. It became the default choice for software developers creating new packages, less for its associated ideology and more for its compatibility with GNU/Linux.

Another thread of software freedom stretching back just as far uses a different approach that eschews any “copyleft” requirement. Most of Stallman’s peers decided to license the copyrights to their software in a very relaxed fashion, giving anyone who received the source code the right to use it as if they owned it, with very few restrictions.

Originally associated with variants of Unix, these “permissive” licenses took their names from the universities at Berkeley and Massachusetts: the BSD and MIT licenses. These licenses allow you to do almost anything with the associated software, including making it closed, proprietary software to which the four freedoms no longer apply. This is also a source of controversy, as some people consider it wrong to take open source software and prevent others in the future from using, studying, modifying, and distributing it.

Over time another permissive copyright license has become very widely used. Associated with the large and successful Apache Software Foundation, the Apache license is similar to the earlier BSD and MIT licenses but has added protections for the communities using it, notably related to software patents. Both the Apache license and the GPL have spread independently of their associated communities, and they’ve been joined by a range of other copyright licenses crafted by different communities for different purposes. The Open Source Initiative (OSI) was established in 1998 to validate whether such licenses truly delivered software freedom, using the “open source definition” as its rubric.

The case for the GPL’s decline The idea that the GPL is in decline appeared last summer when 451 Group analyst Matthew Aslett built on comments defending Oracle’s open source adjustments by Eclipse Foundation representative Ian Skerrett. His blog posting used data gathered by Black Duck, a firm providing due diligence services to companies concerned about open source licensing fears. He wrote: “According to Black Duck’s figures the proportion of open source projects using the GPL family of licenses has fallen to 61% today from 70% in June 2008, while the GPLv2 has fallen to 45% from 58% three years ago.”

The cause of the decline was not the relicensing of existing projects; that rarely happens, and as Aslett noted, the actual number of GPL-licensed projects had increased. But a larger proportion of new projects were choosing permissive licenses. Aslett returned to the topic in another blog in December. His focus remained on the interactions comprising commercial exploitation of open source software, and he predicted the trend continuing.

The case for stasis As analyst Stephen O’Grady pointed out at the time, the GPL is still a more widely used open source license than the MIT, Artistic, BSD, Apache, MPL, and EPL options all put together. Aslett’s assertions raised the ire of the free software supporters, who mounted a defense at the FOSDEM conference in Brussels in February.

Two presentations were especially notable. Red Hat lawyer Richard Fontana mounted a spirited and entertaining call for fresh focus on the problems the GPL faces in adoption by new projects, especially in the cloud. FSF executive director John Sullivan was more serious, with a presentation raising questions about the data Aslett used and suggesting that data derived by analyzing licensing in the Debian distribution of GNU/Linux showed a growth, not a decline in GPL adoption. Aslett’s response accepted criticism of his numbers, while expressing surprise that Sullivan was placing much weight on his analysis of Debian, a surprised shared by the Debian project leader Stefano Zacchiroli.

The probable reality To sum all that up, the best answer to the question of the GPL’s decline: It depends on what you’re looking for. If you’re interested in commercial exploitation of open source, the statistics you select say yes, there’s a steady drift to permissive licenses. If you’re focused on software freedom advocacy and ideology, the statistics appear unreliable and even hint that GPL is increasing. And for those of us trying to take in both outlooks? Well, it needs interpretation!

I don’t agree with Bruce Byfield’s assertions that it’s the result of a sequence of strategic errors by the FSF. I also don’t agree with analyst Donnie Berkholz (who appears to break Fleury’s Rule of not speaking for others you don’t know) that the GPL isn’t needed any more. What we’re really seeing here is a correction to an aberration that arose in the glory years of the growth of commercial open source strategies and startups in the middle of the last decade. The peak in GPL usage in commercial open source in 2005 is especially clear from the graphs in Aslett’s first report. This effect is normalization following the removal of an artificial stimulus; it’s not a decline.

Around that time, companies were flocking to open source for the first time and choosing to ape the strategy of database company MySQL, who selected the GPL not to promote Stallman’s vision of digital liberty but rather to exploit the fears of corporate legal advisors about the GPL. While open source licenses offer everyone the freedom to use the software for any purpose, many companies were concerned that the GPL might force them to open up all their internal workings to the world.

They asked for legal advice, and as always happens when you ask your lawyer for business advice (instead of making business decisions and asking your lawyer to help you achieve them legally) they were told to play it safe and buy a proprietary license to MySQL. This dual-license model depends on two details: the software developer owning all the copyrights so that they can provide different license terms for it to paying and nonpaying users, and the use of the scariest open source license possible in the eyes of inexperienced legal advisers.

As the market has developed, businesses have evolved their strategies, and more and more legal advisers in business have gained an understanding of open source. As a result, the effectiveness of strategies involving scaring customers into buying proprietary licenses for open source software has declined. At the same time, the market has needed more and more mature strategies for working on open source. Often — as is now the case in cloud computing, where there are high stakes and consequent high politics — these strategies involve working with others rather than maintaining tight control for sole exploitation.

The removal of the imperative to scare customers into paying has resulted in commercial open source exploiters swinging to the opposite extreme and picking permissive licenses to allow multivendor involvement, as both O’Grady and Aslett noted. That’s why newcomers are picking permissive licenses rather than copyleft ones. But the free software movement still exists and is still strong.

The GPL is growing too, with new work and new lines of code being constantly released by believers in copyleft. In particular, innovative and energetic distributed projects are using GPL-family licenses, like Freedom Box, the Tahoe-LAFS filesystem, MediaGoblin, SparkleShare, and many others you probably haven’t heard of unless you watch the free software world. Many of these projects have businesses associated with them; commercial open source is not synonymous with permissive licensing.

The apparent conflict between these two licensing approaches seems to me to be more a manufactured dichotomy, a reflection of the age-old disagreement about which freedom should be sacrificed to facilitate the rest — the freedom to close open source, or the freedom to use software derived from open source. Outside that conflict, both permissive and copyleft licensing remain strong and growing, just like open source.

This article, “Is GPL licensing in decline?,” was originally published at InfoWorld.com. Read more of the Open Sources blog and follow the latest developments in open source at InfoWorld.com. For the latest business technology news, follow InfoWorld.com on Twitter.