As I've noted before, it's pretty well established that the GNU GPL stands up in the courts: gone are the days when detractors of copyleft could claim it would "never work". But the GPL is still under attack, only in more subtle ways, so the open source world can't just sit back and relax.
The founder, Harald Welte, started to get active with GPL enforcement in late 2003, where he discovered the first bunch of companies violating the GPL in software he wrote for the netfilter/iptables project.
After some time, he discovered that the number of GPL violations was far bigger than expected, as is the number of Free Software projects whose copyrights are mistreated / abused. Therefore, the gpl-violations.org project was officially started in January 2004.
During 2004, more and more cases of infringement were discovered, mostly in the embedded networking market. The first preliminary injunction in favor of the GPL (and the gpl-violations.org project) was granted in mid-2004.
Over time, some other Linux kernel developers have transferred their rights in a fiduciary license agreement to enable the successful gpl-violations.org project to enforce the GPL in cases where no code originally written by Harald Welte was used / infringed upon.
By June 2006, the project has hit the magic "100 cases finished" mark, at an exciting equal "100% legal success" mark. Every GPL infringement that we started to enforce was resolved in a legal success, either in-court or out of court.
Over 100 cases is an astonishing achievement by one of the unsung heroes of the free software world.
As you might expect, the kind of infringement case that Welte is involved with is evolving, not least because the GPL is becoming so well established. Here's the latest:
Right now I'm facing what I'd consider the most outrageous case that I've been involved so far: A manufacturer of Linux-based embedded devices (no, I will not name the company) really has the guts to go in front of court and sue another company for modifying the firmware on those devices.
More specifically, the only modifications to program code are on the GPL licensed parts of the software. None of the proprietary userspace programs are touched! None of the proprietary programs are ever distributed either.
As Welte says, this really is outrageous: it's GPL'd code, and the embedded system manufacturer is somehow trying to claim that it has the right to stop someone else from using and modifying that code on those devices – as if the hardware made any difference. But the whole point of the GPL is that others must be able to take software distributed under it and use it as they wish.
I suspect that with some careful explanation from Welte (and others), the company will see that it doesn't have a case, and the court action will be quietly dropped. On the other hand, if the case were to go forward and resulted in a win for the company concerned, it would represent a major problem for the GPL. Stay tuned...