FreeGameDev

http://www.gnu.org/licenses/license-rec ... tions.html

For those that need a hint what license to choose for their project (but of course this is not exactly a neutral opinion )

I must say I'm totally with Poul Henning-Kamp (and others) on this one: "The GPL is a joke".
But of course, that's not really a neutral opinion either :P

IMO, the real problem with (almost) all copyleft licenses is that they, despite containing a dozen pages of legalese foo, fail to unambiguously define the most important terms.
Prominent example: "Derivate work" in cc licenses.

I like the GPL for what its idea is and how it has managed to get big cooperations to cooperate on single software projects, but obviously it is not perfect and in general such licenses are hard to enforce (unless you have the pocket money to go through a long court case).

But in the specific point you mention, I don't quite share your critique.
You have to think about this from a legal point of view and not from that of a technician or programmer (or any other logically thinking individual ). It is basically impossible to cover all sorts of derivative works possibilities in the form of text, and if you do so never the less, it will just lend to lawyers to use it as a guideline to find foolproof loop-holes in your license agreement.
If you leave it a bit ambiguous on purpose however the judge can decide on the "intend" of the license, which can be both in your favor or not, but in the case of blatant intends of circumventing the license agreement more often then not will help you against these license violators (But IANAL).
That said... you would still have to have the spare money to take it to court...

Edit: Actually this can probably be moved to the legal forum... totally forgot about that one when posting this