It's a pity that so much (virtual) ink about open source has to be about legalities rather than technical issues. While I find the law interesting, I don't think it's as much fun or as fascinating as the technology. But, for the foreseeable future, lawyers are going to play a big role in the future of technology -- sad as that may be.
In particular, the enforceability of the GPL in U.S. courts has been the subject of much discussion since SCO launched its lawsuit against IBM back in 2003. (Actually, the discussion started prior to that, but it really picked up steam after that.)
This story on Groklaw provides an interesting footnote in the development in the legal progress of the GPL. As usual, Groklaw has all the details you could want on the story, but the short version is this: Drew Technologies created some software under the GPL based on standards created by the Society of Automotive Engineers (SAE). SAE then tried to pull a SCO, claiming ownership of the software because it was created using their material as a reference.
The legality of the GPL was not ruled on as part of DrewTech v. SAE, but it apparently played a role in the settlement. Eric Grimm, attorney for Drew Technologies, says that SAE "surrendered to the GPL."
SAE agrees to drop its claims (and therefore to give up any contention that it owns the software). This paves the way for the software to remain permanently open under the terms of the GPL.
Actually, from where I'm sitting, it looks like the GPL was only a small part of the case: It could have been almost any open source or free software license in question here. However, it would appear that the GPL was strong enough that SAE (or SAE's lawyers) decided that the company didn't have much of a case.
So, here we are again -- the GPL makes it to court in the U.S., but the case is settled without any ruling on the license itself. Will the GPL ever get its day in court? If so, will it emerge unscathed?